JPH0121534B2 - - Google Patents
Info
- Publication number
- JPH0121534B2 JPH0121534B2 JP14865881A JP14865881A JPH0121534B2 JP H0121534 B2 JPH0121534 B2 JP H0121534B2 JP 14865881 A JP14865881 A JP 14865881A JP 14865881 A JP14865881 A JP 14865881A JP H0121534 B2 JPH0121534 B2 JP H0121534B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- substrate
- vapor deposition
- magnetic layer
- layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000000758 substrate Substances 0.000 claims description 25
- 239000007789 gas Substances 0.000 claims description 23
- 238000007740 vapor deposition Methods 0.000 claims description 17
- 238000004519 manufacturing process Methods 0.000 claims description 13
- 238000000034 method Methods 0.000 claims description 12
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 6
- 239000001301 oxygen Substances 0.000 claims description 6
- 229910052760 oxygen Inorganic materials 0.000 claims description 6
- 230000008021 deposition Effects 0.000 claims description 5
- 238000001704 evaporation Methods 0.000 claims description 5
- 230000008020 evaporation Effects 0.000 claims description 5
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 5
- 239000000696 magnetic material Substances 0.000 description 5
- 239000010409 thin film Substances 0.000 description 5
- 238000004804 winding Methods 0.000 description 5
- 229910017052 cobalt Inorganic materials 0.000 description 4
- 239000010941 cobalt Substances 0.000 description 4
- 238000000151 deposition Methods 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 239000006247 magnetic powder Substances 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 229910001566 austenite Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000003490 calendering Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 238000007733 ion plating Methods 0.000 description 1
- 230000005415 magnetization Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 238000001771 vacuum deposition Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
- G11B5/85—Coating a support with a magnetic layer by vapour deposition
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/0021—Reactive sputtering or evaporation
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing Of Magnetic Record Carriers (AREA)
- Thin Magnetic Films (AREA)
Description
【発明の詳細な説明】
本発明は蒸着による磁気記録媒体の製造方法に
関し、特に走行する基板上に磁性層を形成するこ
とを目的とするものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a magnetic recording medium by vapor deposition, and is particularly aimed at forming a magnetic layer on a moving substrate.
一般的に現在提示されている磁気記録媒体とし
ては、塗布型、磁性薄膜型が知られている中でも
塗布型は、磁性体であるγ−Fe2O3やFeを、適当
なバインダーと混合して基板上に塗布した後、磁
場配向や乾燥、カレンダー工程を経て磁気記録媒
体としての特性を得ているもので、この塗布型が
現在では主流を占めている。この塗布型の未来指
向として、高抗磁力化、磁性粉の高密度化、磁性
層の薄型等が示されている。しかし上述のように
磁性粉をバインダーを介して基板上に塗布する方
法では、基本的に磁性粉の充填率におのずから限
界があり高密度化、薄型の防げとなつているのが
現状である。 Currently available magnetic recording media generally include coated type and magnetic thin film type. Of these, coated type is a mixture of magnetic materials such as γ-Fe 2 O 3 and Fe with a suitable binder. After being coated onto a substrate, it undergoes magnetic field orientation, drying, and calendering processes to obtain properties as a magnetic recording medium, and this coating type is currently the mainstream. Future trends for this coating type include higher coercive force, higher density of magnetic powder, and thinner magnetic layer. However, as described above, in the method of applying magnetic powder onto a substrate via a binder, there is basically a limit to the filling rate of the magnetic powder, and the current situation is that high density and thinness cannot be achieved.
そこで高密度、薄膜化を目的として、電気メツ
キによる方法や真空中による、スパツタ法、イオ
ンプレイテイング法、蒸着法等が提案されてき
た。これらの方法によると、磁性材料を基板上に
直接薄膜として形成できるので前記の塗布型にな
い特長のある磁気記録媒体が提供できる。しかし
ながらこれらの方法は一枚の磁気シートを作る場
合には条件管理も十分であり、優れた磁気的、物
理的特性が得られるものであるが、量産という点
からは未だ解決されていない問題点も多く、また
特に磁気テープ様の長尺物において優れた物理的
特性を得る方法は知られていなかつた。 Therefore, methods using electroplating, vacuum sputtering, ion plating, vapor deposition, etc. have been proposed for the purpose of high density and thin film formation. According to these methods, since the magnetic material can be formed as a thin film directly on the substrate, it is possible to provide a magnetic recording medium with features not found in the above-mentioned coating type. However, although these methods allow for sufficient control of conditions when producing a single magnetic sheet and provide excellent magnetic and physical properties, there are still unresolved problems in terms of mass production. Moreover, there was no known method for obtaining excellent physical properties, especially in long objects such as magnetic tapes.
本発明は基板を走行させ、その表面に連続的に
蒸着を行なう製造方法であり、特に蒸着をガス雰
囲気中で行なうにあたつて同一ガスにより磁性層
と非磁性層の２層構造を極めて簡単に行なうもの
である。以下本発明の一実施例を図面にもとづい
て説明する。 The present invention is a manufacturing method in which a substrate is moved and vapor deposition is continuously performed on the surface of the substrate.In particular, when vapor deposition is performed in a gas atmosphere, it is extremely easy to form a two-layer structure of a magnetic layer and a nonmagnetic layer using the same gas. It is something that is done. An embodiment of the present invention will be described below based on the drawings.
第１図は本実施例における製造装置の一例を示
す正面図である。本装置は基板走行系の少なくと
も一部を真空蒸着雰囲気におくこと、およびガス
の供給ノズルを２本有することが特徴である。ま
ず１は、排気管２を経て真空排気装置３に配管さ
れ10-3Torr以下となつた真空槽である。この真
空槽中には長尺状の基板（ここではテープ基体）
４の走行系が内蔵されており、基板走行系は、基
板巻出軸５（逆走行においては巻取軸）とフリー
ローラ６，７蒸着円筒８及び巻取軸９（逆走行に
おいては巻出軸）から成つている。なお上記蒸着
円筒８は第１図中には示していない熱媒系により
一定温度に保たれている。基板走行系に対し蒸着
系は、蒸発熱源９、ルツボ１０およびルツボ中の
磁性材料蒸着源１１から成る。本実施例において
は磁性材料としてコバルト（Co）を使用した。
熱源９により加熱されたコバルトは溶解した後原
子状となつて蒸発を開始するが、この蒸発原子は
固定マスク１２に制限されて第１図に示す斜線部
分１３の範囲でのみ、蒸着円筒８上の基板４に到
達する。ここで固定マスク１２の位置は図示の場
合のみに限定されるものではなく固定マスクの位
置により蒸着された磁性薄膜の磁気特性を変化さ
せることができるものであり、必要に応じて適当
な位置に設けられるものである。固定マスク１２
の上部に２本のガス供給ノズル１４，１５を設け
る。本実施例で非磁性層を得るにあたり、酸化零
囲気を得るためガスは酸素やオゾンが有効であつ
た。ガス供給ノズル１４からは、ガスが蒸発原子
１３内で拡散する状態となるような矢印Ａの方向
に吹き出され、磁性層の所望の磁気特性を得るた
めのガス零囲気用が形成される。他方のガス供給
ノズル１５は蒸着円筒８の回転方向（矢印Ｃ）に
対する蒸発原子の到達範囲の終り、すなわち入射
角の低い部分で局部的な方向（矢印Ｂ方向）に向
けてガスを供給する。すなわち該部分では磁性体
に酸素を与えて酸化物として非磁性を得るもので
ある。なお１６は基板走行系のうちの基板の送り
出し、巻取り部分と、蒸着室とに分ける分離壁で
ある。 FIG. 1 is a front view showing an example of the manufacturing apparatus in this embodiment. This apparatus is characterized in that at least a portion of the substrate transport system is placed in a vacuum deposition atmosphere, and that it has two gas supply nozzles. First, 1 is a vacuum chamber that is connected to a vacuum exhaust device 3 via an exhaust pipe 2 and has a pressure of 10 -3 Torr or less. Inside this vacuum chamber is a long substrate (here, a tape substrate).
4 running system is built in, and the substrate running system consists of a substrate unwinding shaft 5 (winding shaft when running in reverse), free rollers 6, 7, vapor deposition cylinder 8, and winding shaft 9 (winding shaft when running in reverse). axis). The vapor deposition cylinder 8 is kept at a constant temperature by a heat medium system not shown in FIG. In contrast to the substrate transport system, the evaporation system consists of an evaporation heat source 9, a crucible 10, and a magnetic material evaporation source 11 in the crucible. In this example, cobalt (Co) was used as the magnetic material.
After the cobalt is heated by the heat source 9, it becomes atomic and starts to evaporate after being melted. However, the evaporated atoms are restricted by the fixed mask 12 and only reach the area of the shaded area 13 shown in FIG. 1 on the evaporation cylinder 8. reaches the substrate 4. Here, the position of the fixed mask 12 is not limited to the case shown in the figure, but the magnetic properties of the deposited magnetic thin film can be changed depending on the position of the fixed mask, and the position of the fixed mask 12 can be adjusted to an appropriate position as necessary. It is provided. Fixed mask 12
Two gas supply nozzles 14 and 15 are provided at the upper part of the gas supply nozzle. In obtaining the nonmagnetic layer in this example, oxygen and ozone were effective gases to obtain a zero oxidation atmosphere. From the gas supply nozzle 14, the gas is blown out in the direction of the arrow A such that the gas is diffused within the vaporized atoms 13, thereby forming a zero gas atmosphere for obtaining the desired magnetic properties of the magnetic layer. The other gas supply nozzle 15 supplies gas in a local direction (in the direction of arrow B) at the end of the reach of the evaporated atoms with respect to the rotational direction of the deposition cylinder 8 (arrow C), that is, in a portion where the incident angle is low. That is, in this part, oxygen is given to the magnetic material to obtain non-magnetic properties as an oxide. Reference numeral 16 denotes a separation wall that divides the substrate feeding and winding portion of the substrate transport system into a vapor deposition chamber.
上記の構成の製造装置を用いれば、基板４が巻
出軸５、蒸着円筒８、巻取軸９の順に導びかれて
走行している時、蒸着円筒８上で一定温度に保た
れた状態で、対向する蒸着源１１からこの基板４
の表面にコバルト原子が到達し、蒸着薄膜が形成
される。ここでガス供給ノズル１４により矢印Ａ
方向に吹き出された酸素により第２図に示すよう
に基板上にはコバルトの磁性層１７が形成され
る。さらに同一工程において、次なるガス供給ノ
ズル１５により矢印Ｂ方向に吹き出された酸素に
よつつ、前記磁性層１７の上部に非磁性層１８が
得られる。すなわち基板上に磁性層１７と非磁性
層１８を順次設けた磁気記録媒体が得られるもの
である。 If the manufacturing apparatus with the above configuration is used, when the substrate 4 is guided and travels in the order of the unwinding shaft 5, the deposition cylinder 8, and the take-up shaft 9, the temperature is maintained at a constant temperature on the deposition cylinder 8. Then, from the opposing vapor deposition source 11, this substrate 4 is
Cobalt atoms reach the surface and form a deposited thin film. Here, the gas supply nozzle 14
Due to the oxygen blown out in the direction, a magnetic layer 17 of cobalt is formed on the substrate as shown in FIG. Furthermore, in the same process, a non-magnetic layer 18 is obtained on top of the magnetic layer 17 by oxygen blown out in the direction of arrow B by the next gas supply nozzle 15. That is, a magnetic recording medium in which a magnetic layer 17 and a nonmagnetic layer 18 are sequentially provided on a substrate can be obtained.
第３図は磁化特性等の諸特性を向上させるため
に多層構造とした磁気記録媒体を示す。この場合
は上記で形成した第２図の磁気記録媒体を再びこ
の製造装置中で走行させ蒸着させることによつて
第３層としての磁性層１７′、第４層としての非
磁性層１８′を得ることができ、さらにもう一度
この製造装置中でガス供給ノズル１５からの酸素
供給を停めて走行および蒸着を行なえば第５層の
磁性層１７″を得ることができる。また上記の多
層構造の磁気記録媒体を連続的に得るには、上記
の製造装置を３基直列に並べ、第１基で磁性層１
７と非磁性層１８を形成し、これをそのまま第２
基に導入して磁性層１７′と非磁性層１８′を形成
し、さらに第３基では磁性層１７″のみを形成す
ればよい。なおさらに多層構造の場合も上記同様
の繰り返しで実現可能である。また上記実施例で
は蒸着源にコバルトCoを用いたが他の金属、２
種以上の金属の組み合わせでもよいことは明らか
である。 FIG. 3 shows a magnetic recording medium having a multilayer structure to improve various properties such as magnetization properties. In this case, the magnetic recording medium shown in FIG. 2 formed above is run again in this manufacturing apparatus and deposited, thereby forming the magnetic layer 17' as the third layer and the non-magnetic layer 18' as the fourth layer. Furthermore, if the supply of oxygen from the gas supply nozzle 15 is stopped in this manufacturing apparatus and running and vapor deposition are performed again, the fifth magnetic layer 17'' can be obtained. In order to continuously obtain recording media, three of the above-mentioned manufacturing devices are arranged in series, and the first device produces the magnetic layer 1.
7 and a nonmagnetic layer 18, and this is directly applied to the second layer.
It is sufficient to introduce the magnetic layer 17' and the non-magnetic layer 18' into the base, and then form only the magnetic layer 17'' in the third base.Furthermore, a multilayer structure can also be realized by repeating the same process as above. In the above embodiment, cobalt Co was used as the vapor deposition source, but other metals,
It is clear that a combination of more than one type of metal may be used.
上記の実施例からも明らかなように本発明は、
走行する基板に対してガス中蒸着とし、第１のノ
ズルからのガスによつて磁性層を蒸着形成し、第
２のノズルからの前記と同一のガスによつて非磁
性層を蒸着形成することを特徴とするものである
から、同一蒸着系内でさらに同一のガスを用いて
磁性層と非磁性層を得ることができ、製造工程が
極めて単純化され、また蒸着条件等も管理し易く
なり、均質な製品を多量に製造することが可能で
ある。また磁性層、非磁性層の金属材料が同一で
あることは蒸着効率を向上させ、コストの低下も
実現できる。さらに多層構造の磁気記録媒体も全
く同様の工程の繰り返しにより実現可能であり、
磁気特性の向上に大きな効果があるものである。
以上のように本発明によれば高密度記録の可能な
蒸着薄膜による磁気記録媒体を多量にかつ安価
に、非常に均質性を保つて製造できる、優れた磁
気記録媒体の製造方法を提供できるものである。 As is clear from the above examples, the present invention
Vapor deposition is performed in a gas on a traveling substrate, and a magnetic layer is vapor-deposited using gas from a first nozzle, and a non-magnetic layer is vapor-deposited using the same gas as described above from a second nozzle. Because of this, it is possible to obtain a magnetic layer and a non-magnetic layer using the same gas in the same vapor deposition system, which greatly simplifies the manufacturing process and makes it easier to control vapor deposition conditions. , it is possible to produce homogeneous products in large quantities. Furthermore, if the magnetic layer and the nonmagnetic layer are made of the same metal material, the deposition efficiency can be improved and costs can be reduced. Furthermore, a magnetic recording medium with a multilayer structure can be realized by repeating exactly the same process.
This has a great effect on improving magnetic properties.
As described above, according to the present invention, it is possible to provide an excellent method for manufacturing a magnetic recording medium, which enables high-density recording to be performed in large quantities and at low cost, while maintaining extremely high homogeneity. It is.
第１図は本発明の一実施例を実現し得る製造装
置の例を示す正面図、第２図は本発明による磁気
記録媒体の断面図、第３図は多層構造の磁気記録
媒体の断面図である。
１……真空槽、４……基板、５……巻出軸、８
……蒸着円筒、９……巻取軸、１１……蒸着源、
１４，１５……ガス供給ノズル、１７……磁性
層、１８……非磁性層。
FIG. 1 is a front view showing an example of a manufacturing apparatus that can realize an embodiment of the present invention, FIG. 2 is a cross-sectional view of a magnetic recording medium according to the present invention, and FIG. 3 is a cross-sectional view of a multilayer magnetic recording medium. It is. 1... Vacuum chamber, 4... Board, 5... Unwinding shaft, 8
... Vapor deposition cylinder, 9... Winding shaft, 11... Vapor deposition source,
14, 15...Gas supply nozzle, 17...Magnetic layer, 18...Nonmagnetic layer.
Claims (1)
10-3Torr以下の真空中に置いてこの真空中に前
記基板を走行状態で導入し、この真空中で基板表
面を蒸着雰囲気にするとともに、第１の管により
供給されたガスにより上記蒸着雰囲気をガス中蒸
着条件下になして基板上に磁性層を形成し、第２
の管により供給された上記と同一のガスにより蒸
着雰囲気の端部で非磁性層を形成することを特徴
とする磁気記録媒体の製造方法。 ２ 第１および第２の管から供給されるガスが酸
素またはオゾンであることを特徴とする特許請求
の範囲第１項記載の磁気記録媒体の製造方法。[Claims] 1. Part of the mechanism for running the tape-shaped substrate
The substrate is placed in a vacuum of 10 -3 Torr or less and introduced in a running state into this vacuum, and the substrate surface is made into a vapor deposition atmosphere in this vacuum, and the above vapor deposition atmosphere is created by the gas supplied from the first tube. A magnetic layer is formed on the substrate under gaseous evaporation conditions, and a second magnetic layer is formed on the substrate.
A method of manufacturing a magnetic recording medium, characterized in that a nonmagnetic layer is formed at the end of a deposition atmosphere using the same gas as above supplied through a tube. 2. The method for manufacturing a magnetic recording medium according to claim 1, wherein the gas supplied from the first and second tubes is oxygen or ozone.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14865881A JPS5850629A (en) | 1981-09-18 | 1981-09-18 | Production of magnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14865881A JPS5850629A (en) | 1981-09-18 | 1981-09-18 | Production of magnetic recording medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5850629A JPS5850629A (en) | 1983-03-25 |
| JPH0121534B2 true JPH0121534B2 (en) | 1989-04-21 |
Family
ID=15457724
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14865881A Granted JPS5850629A (en) | 1981-09-18 | 1981-09-18 | Production of magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5850629A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04500198A (en) * | 1988-08-19 | 1992-01-16 | リージェンツ・オブ・ザ・ユニバーシティ・オブ・ミネソタ | Preparation of superconducting ceramic oxide using ozone |
| US9885110B2 (en) | 2014-08-06 | 2018-02-06 | United Technologies Corporation | Pressure modulated coating |
-
1981
- 1981-09-18 JP JP14865881A patent/JPS5850629A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5850629A (en) | 1983-03-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4387136A (en) | Magnetic recording medium and apparatus for preparing the same | |
| EP0151445B1 (en) | Production of magnetic recording medium | |
| JPH0121534B2 (en) | ||
| KR900001141B1 (en) | Mafnetic recording medium and its producing method there of | |
| JPH083902B2 (en) | Method for manufacturing thin film magnetic recording medium | |
| JPS5850628A (en) | Production of magnetic recording medium | |
| JP2650300B2 (en) | Method for manufacturing perpendicular magnetic recording medium | |
| JPS5814329A (en) | Production of magnetic recording medium | |
| JPH053052B2 (en) | ||
| JP3687557B2 (en) | Thin film magnetic tape manufacturing equipment | |
| JPS58100232A (en) | Manufacture of magnetic recording medium | |
| JPS5860432A (en) | Manufacture of magnetic recording medium | |
| JPH0817050A (en) | Magnetic recording medium | |
| JPH117627A (en) | Magnetic recording medium and its method and device of manufacturing | |
| JPH07114731A (en) | Production of magnetic recording medium | |
| JPS6059536A (en) | Producing device of magnetic thin film | |
| JPS5814327A (en) | Production of magnetic recording medium | |
| JPH057766B2 (en) | ||
| JPS58105433A (en) | Producing device of magnetic recording medium | |
| JPH0334620B2 (en) | ||
| JPH09128751A (en) | Production of magnetic recording medium | |
| JPH04328324A (en) | Manufacture of magnetic recording medium | |
| JPS6262431A (en) | Production of magnetic recording medium | |
| JPH01303623A (en) | Magnetic recording medium | |
| JPH103659A (en) | Apparatus for production of magnetic recording medium and processing therefor |