Structural and magnetic phase transitions in NdCoAsO under high pressures
Walter Uhoya1, Georgiy M Tsoi, Yogesh K Vohra
1Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
Summary
High pressure studies reveal that NdCoAsO undergoes a structural phase transition at 23 GPa. Both magnetic transition temperatures increase with pressure, but the material remains antiferromagnetic and non-superconducting up to 53 GPa.
Area of Science:
- Condensed Matter Physics
- Materials Science
- High-Pressure Physics
Background:
- Investigates NdCoAsO, a quaternary rare-earth transition-metal arsenide oxide.
- NdCoAsO is isostructural to NdFeAsO, a parent phase of high-temperature superconductors.
- Understanding pressure effects on such materials is crucial for exploring novel electronic phases.
Purpose of the Study:
- To investigate structural and magnetic phase transitions in NdCoAsO under high pressures.
- To determine the influence of pressure on magnetic ordering temperatures (Curie and Néel temperatures).
- To identify any structural phase transitions and their pressure-temperature dependence.
Main Methods:
- Four-probe electrical resistance measurements conducted in a designer diamond anvil cell.
- High-pressure X-ray diffraction studies utilizing a synchrotron source.
- Measurements performed across a pressure range up to 53 GPa and temperatures down to 10 K.
Main Results:
- Both ferromagnetic Curie temperature and antiferromagnetic Néel temperature were observed to increase with increasing pressure.
- A structural phase transition from a tetragonal to a new crystallographic phase occurred at 23 GPa at 300 K.
- NdCoAsO remained antiferromagnetic and non-superconducting up to the maximum experimental pressure of 53 GPa.
Conclusions:
- High pressure significantly influences the magnetic and structural properties of NdCoAsO.
- The observed pressure-induced structural transition does not induce superconductivity in this material.
- A comprehensive P-T phase diagram for NdCoAsO is presented, detailing its behavior from ambient conditions to 53 GPa and 10 K.
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