JPS5969499A - Manufacture of pbtio3 single crystal - Google Patents

Abstract

PURPOSE:To form a large-sized PbTiO3 single crystal having a good quality and high electric resistance, by adding a slight amount of trivalent metallic oxides in the manufacture of a single crystal consisting essentially of PbTiO3. CONSTITUTION:PbO and TiO2 are mixed with a slight amount of >=1 components among trivalent metallic oxides in prescribed ratios, and the mixture is filled in a platinum crucible to allow to stand at about 1,100 deg.C, for about 5hr. A PbTiO3 single crystal is grown by cooling said mixture gradually at about 10 deg.C/ hr rate to about 700 deg.C. The obtained crystal is dissolved in hot nitric acid to separate from a flux. A slight amount of components are Sb2O3, Bi2O3, Ge2O3 or the like, and the quantities to be added are about 0.01-10mol%.

Description

[Detailed description of the invention] The invention is based on PbT used as a piezoelectric or pyroelectric material.
The present invention relates to a method for manufacturing an iOs single crystal.

PbTi0a is a ferroelectric material with a perovskite structure similar to B a T i 03, and one Curie point is 49
Because it has a high temperature of 0°C, it is expected to be a piezoelectric and focused material that can be used stably over a relatively wide range of temperatures.

A lot of research has been done on the growth of Pl)Ti03 single crystals, but so far.

Laughing Blue is a type of material for which high-quality, large-sized single crystals have not yet been obtained.

The reason why it is difficult to grow high-quality PbTiOs single crystals is that when single crystals are formed by known flux methods, pulling methods, sputtering methods, etc., pbo evaporates in a high temperature range and becomes a semiconductor. Therefore, the resistance value is 106ΩΦcm
There was a problem that polarization could not be achieved by applying a high electric field at high temperature because only a certain degree of polarization could be obtained.

Therefore, as a result of various experiments, the present inventor found that when producing a single crystal of a composition mainly composed of PbTiOs, by adding a trace amount of one or more of trivalent metal oxides, PbTiOs
By obtaining the knowledge that defects in P b Ti O3 can be compensated for, and by single-crystallizing the composition using known means, we succeeded in producing a high-quality, large-sized, high-resistance P b Ti O3 single crystal. be.

Examples of non-invention will be explained below, but the non-invention is as follows.
Of course, the present invention is not limited to the embodiments illustrated in .

Example After mixing PbO and T i (%) and minor components in the proportions shown in Table 1, the mixture was filled into a platinum crucible, held at 1100°C for 5 hours, and then slowly heated to 700°C at a rate of 10°C/11r. The entire cooled PbTiO3 single crystal was grown.Next, the obtained crystal was separated from the syflux by elution treatment with hot nitric acid.

1. As shown in Table 2, the crystals obtained had a cubic shape of about 20 squares at most. Further, as a result of electrical measurement, the specific resistance was as high as 108 to 109 Ω·cm.

Note that the amount of trivalent metal oxide added is preferably about 0.01 to 10 molty.

Table 2 As explained above, the uninvented PbTiO3 single crystal has a high resistance value and can be polarized by applying a large electric field at high temperatures, so it can be used stably at relatively high temperatures. It can be widely applied as a piezoelectric and pyroelectric material.

In the above example, a p single crystal was obtained by the flux method, but
Other methods may also be used.

Patent applicant: Chichibu Cement Co., Ltd.

Claims (1)

[Claims] A method for producing a PbTi0B single crystal, which is characterized in that a trace amount of one or more of trivalent metal oxides is added when producing a single crystal of a composition containing PbTi01 as a main component.