CN113235165A - Novel Fe1-xTMxPreparation method of S single crystal material - Google Patents

Abstract

The invention discloses novel Fe_1‑xTM_xThe preparation method of the S single crystal material comprises the steps of preparing a transition metal TM, wherein the transition metal TM comprises one of cobalt, nickel and copper elements, x is the stoichiometric number of the TM, and the range of x is more than or equal to 0.01 and less than or equal to 0.5. The method comprises the following steps: step a preparation of Fe_1.6‑xTM_xS₂Polycrystal; step b preparation of K_0.8Fe_1.6‑xTM_xS₂Single crystal; c, preparing an aqueous solution of thiourea and sodium hydroxide; step d adding iron powder, TM powder and K to the solution of step c_0.8Fe_1.6‑xTM_xS₂Obtaining a mixed solution by single crystal; step e, carrying out heat preservation reaction on the mixed solution; step f, washing the solution after the reaction by using water and ethanol to obtain Fe with a tetragonal structure_1‑xTM_xAnd (4) S single crystal. The method successfully dopes transition metal elements into the square-structure FeS single crystal as Fe_1.6‑xTM_xS₂The polycrystal is used as a precursor, the content of transition metal elements is accurately controlled, and K is weakened_0.8Fe_1.6‑xTM_xS₂The reaction between potassium simple substance and sulfur element in the process of single crystal growth has low cost, simple process, nontoxic raw materials, high quality and large size of the prepared single crystal, and can be used for treating Fe_1‑xTM_xThe research on the physical property of S material system and the application of magnetic devices are of great significance.

Description

Preparation method of novel Fe1-xTMxS single crystal material

Technical Field

The invention relates to novel Fe_1-xTM_xA preparation method of S single crystal material belongs to the field of preparation methods of single crystal materials.

Background

In 2016, an iron-based superconductor FeS single crystal is successfully prepared by a hydrothermal method, and the superconducting transition temperature is 4.5K. The FeS superconductor with the tetragonal structure has larger anisotropy and lower upper critical field as the iron-based superconductor with the simplest structure, and meanwhile, the research of angle-resolved photoelectron spectroscopy shows that the FeS superconductor has larger electronic correlation inside the FeS superconductor. Compared with FeSe superconductor with the same structure, FeS has no structural phase transition and electronic liquid crystal phase transition at low temperature, which makes FeS an important material for researching the high-temperature superconducting mechanism and the correlation between the electronic liquid crystal phase and the superconducting transition.

Although the FeS superconducting material has more novel characteristics and abundant physical connotation, the superconducting transition temperature of the FeS superconducting material is lower than that of other iron-based superconductors. According to previous reports, a small amount of Se doping at the S site of the FeS superconductor fails to raise the superconducting transition temperature, and the preparation of a transition metal doped single crystal sample of the FeS superconductor is still unsuccessful due to the great difficulty.

In the traditional preparation method, impurity phases with hexagonal structures are easy to generate, the content of transition metal elements is difficult to control, and meanwhile, potassium simple substances and sulfur elements react violently, so that preparation failure or crystal quality is easy to deteriorate. Therefore, if the content of the transition metal element can be accurately controlled, the intensity of the reaction is weakened, and high-quality tetragonal Fe can be prepared_1-xTM_xS single crystal sample, for studying superconducting mechanism of iron-based superconductor and Fe_1-xTM_xThe practical application of the S material system is greatly facilitated.

Disclosure of Invention

In order to solve the problems of the existing preparation method, the invention aims to overcome the defects of the prior art and provide a preparation methodHigh-quality novel Fe_1-xTM_xThe preparation method of S single crystal material has low cost, nontoxic raw material and simple operation, and Fe is used_1.6-xTM_xS₂The polycrystal is used as a precursor to accurately control the content of transition metal elements and simultaneously weaken K_0.8Fe_1.6-xTM_xS₂Reaction between potassium element and sulfur element in the process of single crystal growth, with K_0.8Fe_1.6-xTM_xS₂The single crystal is taken as a substrate material, interlayer potassium ions are de-intercalated by a hydrothermal method, transition metal elements are successfully doped into the FeS single crystal with the square structure, and high-quality, large-size and stable Fe in the air is prepared_1-xTM_xAnd (4) S single crystal.

In order to achieve the purpose of the invention, the invention adopts the following technical scheme: novel Fe_1-xTM_xThe preparation method of the S single crystal material comprises the following steps:

a. mixing and grinding iron powder, TM powder and sulfur powder, and sintering for 12-48 hours to prepare Fe_1.6-xTM_xS₂The TM is any one of cobalt, nickel and copper elements;

b. using Fe in step a_1.6-xTM_xS₂Mixing the polycrystal with the simple substance potassium, reacting for 12-24 hours at high temperature, and cooling to obtain K_0.8Fe_1.6-xTM_xS₂Single crystal;

c. preparing a mixed solution of thiourea and sodium hydroxide;

d. mixing iron powder, TM powder and K_0.8Fe_1.6-xTM_xS₂Adding single crystal into the mixed solution in the step c, and adding iron powder, TM powder and K_0.8Fe_1.6-xTM_xS₂Storing the mixed solution of the single crystal under the condition of inert gas;

e. d, keeping the temperature of the mixed solution obtained in the step d for reaction;

f. washing the reacted mixed solution with water and ethanol to obtain Fe_1-xTM_xS layered single crystal.

Wherein:

in the step a, the molar ratio of the iron powder to the TM powder to the sulfur powder is (0-1): (0-1): 1; the sintering temperature is 400 ℃ or 500 ℃;

in step b, Fe_1.6-xTM_xS₂The molar ratio of polycrystal to simple substance potassium is 1: 0.8; the reaction temperature is 950-1020 ℃; the cooling rate is 4 ℃/hour or 5 ℃/hour;

in the step c, the molar ratio of water, sodium hydroxide and thiourea in the mixed solution is (150-200): 1: 1;

in step d, iron powder, TM powder, K_0.8Fe_1.6-xTM_xS₂The molar ratio of the single crystal is (1-2): (1-2): 1;

in the step e, the heat preservation reaction refers to placing the mixed solution in an oven, and performing heat preservation reaction for 2-4 days at 120 ℃;

has the advantages that: compared with the prior art, the invention has the following outstanding characteristics and obvious advantages:

1. in the invention, Fe_1.6-xTM_xS₂The polycrystal is used as a precursor, the preparation process is safe and simple, and the content of the transition metal element can be accurately controlled;

2. the invention weakens K_0.8Fe_1.6-xTM_xS₂The reaction between the potassium simple substance and the sulfur element in the process of single crystal growth improves the quality and the stability of a single crystal sample, and the obtained Fe_1-xTM_xThe size of the S single crystal can reach centimeter magnitude.

Drawings

FIG. 1 shows Fe prepared in example 1 of the present invention_1-xTM_xX-ray diffraction pattern of S single crystal, wherein TM is cobalt element.

Detailed Description

The present invention will be described in further detail with reference to examples, so that the objects, technical solutions and advantages of the present invention will be more clearly understood.

Example 1:

a. preparation of Fe_1.6-xCo_xS₂Polycrystal: mixing iron powder, cobalt powder and sulfur powder according to Fe_1.6-xCo_xS₂Weighing atomic ratio, grinding the raw materials in a mortar for more than 30 minutes in an argon atmosphere, sealing the ground sample in a vacuum quartz tube, sintering the quartz tube in a box furnace at 500 ℃ for 24 hours, and cooling to room temperature to obtain Fe_1.6-xCo_xS₂Polycrystal;

b. preparation K_0.8Fe_1.6-xCo_xS₂Single crystal: 1.6g of Fe_1.6-xCo_xS₂The polycrystal and 0.328g of elemental potassium are sealed in a vacuum quartz tube, then the quartz tube is placed in a box furnace to be sintered for 24 hours at 1000 ℃, slowly cooled to 700 ℃ at the speed of 5 ℃/hour, and dissociated to obtain K_0.8Fe_1.6-xCo_xS₂Single crystal;

c. a mixed solution was prepared under an inert atmosphere, and 0.12g of sodium hydroxide and 0.23g of thiourea were added to 10ml of water and sufficiently stirred to obtain a mixed solution.

d. Then press K_0.8Fe_1.6-xCo_xS₂Atomic ratio of Single Crystal in the mixed solution, 0.16g of a mixture of iron powder and cobalt powder was added, followed by 0.24g of K_0.8Fe_1.6-xCo_xS₂Single crystal, and finally sealing the solution in a hydrothermal reaction kettle;

e. putting the hydrothermal reaction kettle into an oven, and reacting for 3 days at the temperature of 120 ℃;

f. after the reaction is finished, repeatedly cleaning the reaction kettle by using water and ethanol to obtain Fe_1-xCo_xS layered single crystal.

Example 2:

a. preparation of Fe_1.6-xNi_xS₂Polycrystal: mixing iron powder, nickel powder and sulfur powder according to Fe_1.6-xNi_xS₂Weighing atomic ratio, grinding the raw materials in a mortar for more than 30 minutes in an argon atmosphere, sealing the ground sample in a vacuum quartz tube, sintering the quartz tube in a box furnace at 450 ℃ for 24 hours, and cooling to room temperature to obtain Fe_1.6-xNi_xS₂Polycrystal;

b. preparation K_0.8Fe_1.6-xNi_xS₂Single crystal: 0.16g of Fe_1.6-xNi_xS₂The polycrystal and 0.328g of elemental potassium are sealed in a vacuum quartz tube, then the quartz tube is placed in a box furnace to be sintered for 24 hours at 1020 ℃, slowly cooled to 700 ℃ at the speed of 5 ℃/hour, and dissociated to obtain K_0.8Fe_1.6-xNi_xS₂Single crystal;

c. a mixed solution was prepared under an inert atmosphere, and 0.12g of sodium hydroxide and 0.23g of thiourea were added to 10ml of water and sufficiently stirred to obtain a mixed solution.

d. Then press K_0.8Fe_1.6-xNi_xS₂Atomic ratio of Single Crystal to the mixed solution 0.16g of a mixture of iron and nickel powders was added, followed by 0.24g of K_0.8Fe_1.6-xNi_xS₂Single crystal, and finally sealing the solution in a hydrothermal reaction kettle;

e. putting the hydrothermal reaction kettle into an oven, and reacting for 3 days at the temperature of 120 ℃;

f. after the reaction is finished, repeatedly cleaning the reaction kettle by using water and ethanol to obtain Fe_1-xNi_xS layered single crystal.

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments, and any other changes or modifications without departing from the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (7)

1. Novel Fe_1-xTM_xThe preparation method of the S single crystal material is characterized by comprising the following steps of:

a. mixing and grinding iron powder, TM powder and sulfur powder, and sintering for 12-48 hours to prepare Fe_1.6-xTM_xS₂The TM is any one of cobalt, nickel and copper elements;

b. using Fe in step a_1.6-xTM_xS₂Mixing the polycrystal with the simple substance potassium, reacting for 12-24 hours at high temperature, and cooling to obtain K_0.8Fe_1.6-xTM_xS₂Single crystal;

c. preparing a mixed solution of thiourea and sodium hydroxide;

d. mixing iron powder, TM powder and K_0.8Fe_1.6-xTM_xS₂Adding single crystal into the mixed solution in the step c, and adding iron powder, TM powder and K_0.8Fe_1.6-xTM_xS₂Storing the mixed solution of the single crystal under the condition of inert gas;

e. d, carrying out heat preservation reaction on the mixed solution in the step d;

f. washing the reacted mixed solution with water and ethanol to obtain Fe_1-xTM_xS layered single crystal.

2. Novel Fe according to claim 1_1-xTM_xThe preparation method of the S single crystal material is characterized by comprising the following steps: in the step a, x is the stoichiometric number of TM and is in the range of 0.01-0.5.

3. Novel Fe according to claim 1_1-xTM_xThe preparation method of the S single crystal material is characterized by comprising the following steps: in said step a, Fe is prepared_1.6-xTM_xS₂The molar ratio of iron powder, TM powder and sulfur powder used by the polycrystal is 0-1: 0-1: 1; the sintering temperature is 350-550 ℃.

4. Novel Fe according to claim 1_1-xTM_xThe preparation method of the S single crystal material is characterized by comprising the following steps: in said step b, K is prepared_0.8Fe_1.6-xTM_xS₂Fe for single crystals_1.6-xTM_xS₂The molar ratio of polycrystal to simple substance potassium is 1: 0.5 to 1; the reaction temperature is 800-1020 ℃; the cooling rate is 4-10 ℃/h.

5. Novel Fe according to claim 1_1-xTM_xThe preparation method of the S single crystal material is characterized by comprising the following steps: in the step c, the molar ratio of water, sodium hydroxide and thiourea in the mixed solution is 150-200: 1-2: 1 to 2.

6. Novel Fe according to claim 1_1-xTM_xThe preparation method of the S single crystal material is characterized by comprising the following steps: in said step d, iron powder, TM powder, K_0.8Fe_1.6-xTM_xS₂The molar ratio of the single crystal is 1-2: 1-2: 0.5 to 1.

7. Novel Fe according to claim 1_1-xTM_xThe preparation method of the S single crystal material is characterized by comprising the following steps: in the step e, the heat preservation reaction means that the mixed solution is placed in an oven and is subjected to heat preservation reaction for 1-5 days at the temperature of 80-180 ℃.

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