CN110922177A - Iron-based oxide superconducting material and preparation method thereof - Google Patents

Abstract

The invention discloses an iron-based oxide superconducting material and a preparation method thereof, wherein iron is used as a base material, and a mixture consisting of elements of niobium, germanium, selenium, nickel, iron, fluorine and oxygen is formed according to a molecular weight group; nb2Ge1Se1Ni3Fe3F2O 14; the mixture is respectively Nb2O5, GeO2, SeO3, Ni3O2, Fe3O4 compound and F2 gas, and the proportion combination sequence of Nb2O5, GeO2, SeO3, Ni3O2 and Fe3O4 compound is as follows: 0.2: 0.6: 2: 2: 5.2. the critical superconducting temperature of the niobium-germanium (Nb 3 Ge) alloy reaches 25K, the niobium-germanium (Nb 3 Ge) alloy is doped with iron, nickel and selenium oxide, the mixture is sintered and ground at high temperature and high pressure, fluorine (F2) is introduced, the high-temperature and high-pressure sintering and grinding are carried out, the superconducting critical temperature (Tc) of the obtained powder material is 57K, and the critical temperature of the existing iron-based superconductor is broken through by 50K.

Description

Iron-based oxide superconducting material and preparation method thereof

Technical Field

The invention relates to the technical field of superconducting materials, in particular to an iron-based oxide superconducting material and a preparation method thereof.

Background

Following copper-based superconducting materials, recent sequential reports of japan and chinese scientists have found a new class of high temperature superconducting materials, iron-based superconducting materials. The website reports of the science journal of the United states that the physical sciences deems that the method is a 'great progress' in the field of high-temperature superconducting research.

In the past years, physical research institutes of Chinese academy of sciences and research teams of Chinese science and technology universities represented by Zhao Xian, Chen Xianhui, Wang nan Lin, Wen Hai Hu and Fang Zhong fai have gained the first-class prize of national natural science due to the outstanding contribution in the aspects of 'discovery of iron-based high-temperature superconductors above 40K and research of a plurality of basic physical properties'. Previously, this prize has been open for 3 consecutive years.

High temperature superconducting means that the resistance of the material drops abruptly to zero at a certain relatively high critical temperature. In 1986, scientists discovered the first high temperature superconducting material, lanthanum barium copper oxide. Since then, copper-based superconducting materials have become a research hotspot for physicists worldwide.

However, until now, the physical world has not formed a consensus view on the high-temperature superconducting mechanism of copper-based superconducting materials, which also makes high-temperature superconducting one of the biggest puzzles in the current condensed state physics. Therefore, many scientists hope to find new high-temperature superconducting materials besides the copper-based superconducting materials, so that the high-temperature superconducting mechanism can be more clear.

Until recently, researchers in China and Japan found that iron-based materials, when mixed with other rare metal compounds, form a superconducting phenomenon at a certain absolute temperature under certain conditions. The research on iron-based superconductors has entered this field.

8 representative articles of iron-based superconductors have been introduced 3801 times by SCI, and 20 major articles have been introduced 5145 times by SCI. The related results are strongly reflected in the international academy, and are specially reviewed or reported as spot tracking by the international well-known academic publications such as Science, Nature, Physics Today, Physics World, and the like. The famous theoretical physicist, university of florida, Peter professor Hirschfeld, states: "one or perhaps not to what I were surprised is that there are so many high quality articles from Beijing that they have indeed entered this (condensed physical republic) line"; professor Steven Kivelson, stanford, usa: what is "surprised is that not only do these results come from china, but importantly they do not come from the united states. "

The current main research direction of iron-based superconduction is to increase the critical absolute temperature of superconduction, and it is reported that the current Chinese research team increases the critical temperature to 50K, and the record is continuously updated in the near future.

Disclosure of Invention

The invention aims to make up for the defects of the prior art and provides an iron-based oxide superconducting material and a preparation method thereof.

The invention is realized by the following technical scheme:

an iron-based oxide superconducting material is prepared from iron as a base material and a mixture of elements including niobium, germanium, selenium, nickel, iron, fluorine and oxygen, and comprises the following components in percentage by molecular weight: nb2Ge1Se1Ni3Fe3F2O 14; the mixture is respectively Nb2O5, GeO2, SeO3, Ni3O2, Fe3O4 compound and F2 gas, and the proportion combination sequence of Nb2O5, GeO2, SeO3, Ni3O2 and Fe3O4 compound is as follows: 0.2: 0.6: 2: 2: 5.2, preparing the super-bulk powdery raw material by a solid-phase reaction method, wherein the superconducting critical temperature (Tc) of the raw material reaches 57K.

A preparation method of an iron-based oxide superconducting material comprises the following steps of firstly mixing Nb2O5, GeiO2, SeO3, Ni3O2 and Fe3O4 compounds according to the proportion of 0.2: 0.6: 2: 2: 5.2, mixing the components, and uniformly stirring the components by a double-helix conical mixer for later use;

placing the mixed Nb2O5, GeiO2, SeO3, Ni3O2 and Fe3O4 compounds in a high-temperature high-pressure sintering furnace with the pressure of 15GPa and the temperature of 1600 ℃, setting the temperature of 900 ℃ and the pressure of 11GPa, simultaneously opening a heating switch and a hydraulic pump, raising the temperature from room temperature to 900 +/-10 ℃ within 30min, pressurizing the uniaxial pressure from a zero-pressure state to 11.0GPa, keeping the temperature and the pressure for 24h, closing the high-temperature high-pressure sintering furnace after the time is up, naturally cooling to room temperature, and taking out the sintered compounds and placing in a room-temperature environment for 3 h;

grinding the cooled compound by an ultrafine powder grinder, wherein the particle size of the ground powdery particles is less than or equal to 10 mu m or more than or equal to 2000 meshes, and placing the ground compound in a room temperature environment for more than 3 h; putting the ground powder into a high-temperature high-pressure sintering furnace again, pumping out air in the furnace, filling F2 gas, closing a valve, setting the temperature to 950 ℃ and the pressure to 11GPa, simultaneously heating and pressurizing, raising the temperature from room temperature to 950 +/-10 ℃ within 50min, pressurizing the uniaxial pressure from a zero pressure state to 11.0GPa, keeping the temperature and the pressure for 24h, cooling to room temperature after the time is up, taking out the sintered columnar compound, and storing in a sealed stainless steel container.

The invention has the advantages that: in the material mixture, niobium and germanium have excellent superconductivity, iron and nickel have wide materials, the price is low, the material is easy to purchase, the selenium material has the effect of eliminating magnetism, the mixture has higher superconductivity of a critical point through solid phase reaction, and the superconductivity of the material mixture exceeds that of iron-based superconductors researched at home and abroad, so that a new superconductivity starting point of the iron-based superconductors is improved;

the critical superconducting temperature of the niobium-germanium (Nb 3 Ge) alloy reaches 25K, the niobium-germanium (Nb 3 Ge) alloy is doped with iron, nickel and selenium oxide, the mixture is sintered and ground at high temperature and high pressure, fluorine (F2) is introduced, the high-temperature and high-pressure sintering and grinding are carried out, the superconducting critical temperature (Tc) of the obtained powder material is 57K, and the critical temperature of the existing iron-based superconductor is broken through by 50K.

The iron and the nickel are magnetic materials, which affect the superconducting performance, but the materials are popular materials, so the price is low and the materials are easy to purchase; and selenium oxide is added, and after high-temperature and high-pressure sintering, the magnetism is eliminated, and the superconducting performance is enhanced.

Detailed Description

An iron-based oxide superconducting material is prepared from iron as a base material and a mixture of elements including niobium, germanium, selenium, nickel, iron, fluorine and oxygen, and comprises the following components in percentage by molecular weight: nb2Ge1Se1Ni3Fe3F2O 14; the mixture is respectively Nb2O5, GeO2, SeO3, Ni3O2, Fe3O4 compound and F2 gas, and the proportion combination sequence of Nb2O5, GeO2, SeO3, Ni3O2 and Fe3O4 compound is as follows: 0.2: 0.6: 2: 2: 5.2, preparing the super-bulk powdery raw material by a solid-phase reaction method, wherein the superconducting critical temperature (Tc) of the raw material reaches 57K.

A preparation method of an iron-based oxide superconducting material comprises the following steps of firstly mixing Nb2O5, GeiO2, SeO3, Ni3O2 and Fe3O4 compounds according to the proportion of 0.2: 0.6: 2: 2: 5.2, mixing the components, and uniformly stirring the components by a double-helix conical mixer for later use;

placing the mixed Nb2O5, GeiO2, SeO3, Ni3O2 and Fe3O4 compounds in a high-temperature high-pressure sintering furnace with the pressure of 15GPa and the temperature of 1600 ℃, setting the temperature of 900 ℃ and the pressure of 11GPa, simultaneously opening a heating switch and a hydraulic pump, raising the temperature from room temperature to 900 +/-10 ℃ within 30min, pressurizing the uniaxial pressure from a zero-pressure state to 11.0GPa, keeping the temperature and the pressure for 24h, closing the high-temperature high-pressure sintering furnace after the time is up, naturally cooling to room temperature, and taking out the sintered compounds and placing in a room-temperature environment for 3 h;

grinding the cooled compound by an ultrafine powder grinder, wherein the particle size of the ground powdery particles is less than or equal to 10 mu m or more than or equal to 2000 meshes, and placing the ground compound in a room temperature environment for more than 3 h; putting the ground powder into a high-temperature high-pressure sintering furnace again, pumping out air in the furnace, filling F2 gas, closing a valve, setting the temperature to 950 ℃ and the pressure to 11GPa, simultaneously heating and pressurizing, raising the temperature from room temperature to 950 +/-10 ℃ within 50min, pressurizing the uniaxial pressure from a zero pressure state to 11.0GPa, keeping the temperature and the pressure for 24h, cooling to room temperature after the time is up, taking out the sintered columnar compound, and storing in a sealed stainless steel container.

Claims (2)

1. An iron-based oxide superconducting material characterized by: taking iron as a base material, taking a mixture consisting of elements of niobium, germanium, selenium, nickel, iron, fluorine and oxygen, and composing according to the molecular weight: nb2Ge1Se1Ni3Fe3F2O 14; the mixture is respectively Nb2O5, GeO2, SeO3, Ni3O2, Fe3O4 compound and F2 gas, and the proportion combination sequence of Nb2O5, GeO2, SeO3, Ni3O2 and Fe3O4 compound is as follows: 0.2: 0.6: 2: 2: 5.2.

2. a preparation method of an iron-based oxide superconducting material is characterized by comprising the following steps: firstly, Nb2O5, GeiO2, SeO3, Ni3O2 and Fe3O4 compounds are mixed according to the proportion of 0.2: 0.6: 2: 2: 5.2, mixing the components, and uniformly stirring the components by a double-helix conical mixer for later use;

placing the mixed Nb2O5, GeiO2, SeO3, Ni3O2 and Fe3O4 compounds in a high-temperature high-pressure sintering furnace with the pressure of 15GPa and the temperature of 1600 ℃, setting the temperature of 900 ℃ and the pressure of 11GPa, simultaneously opening a heating switch and a hydraulic pump, raising the temperature from room temperature to 900 +/-10 ℃ within 30min, pressurizing the uniaxial pressure from a zero-pressure state to 11.0GPa, keeping the temperature and the pressure for 24h, closing the high-temperature high-pressure sintering furnace after the time is up, naturally cooling to room temperature, and taking out the sintered compounds and placing in a room-temperature environment for 3 h;

grinding the cooled compound by an ultrafine powder grinder, wherein the particle size of the ground powdery particles is less than or equal to 10 mu m or more than or equal to 2000 meshes, and placing the ground compound in a room temperature environment for more than 3 h; putting the ground powder into a high-temperature high-pressure sintering furnace again, pumping out air in the furnace, filling F2 gas, closing a valve, setting the temperature to 950 ℃ and the pressure to 11GPa, simultaneously heating and pressurizing, raising the temperature from room temperature to 950 +/-10 ℃ within 50min, pressurizing the uniaxial pressure from a zero pressure state to 11.0GPa, keeping the temperature and the pressure for 24h, cooling to room temperature after the time is up, taking out the sintered columnar compound, and storing in a sealed stainless steel container.