Pressure-induced quantum phase transition in the itinerant ferromagnet UCoGa
Abstract
In this paper, we report the results of a high pressure study of the itinerant 5f-electron ferromagnet UCoGa. The work is focused on probing the expected ferromagnet-to-paramagnet quantum phase transition induced by high pressure and on the general features of the P-T(-H) phase diagram. Diamond anvil cells were employed to measure the magnetization and electrical resistivity under pressures up to ∼ 10 GPa. At ambient pressure, UCoGa exhibits collinear ferromagnetic ordering of uranium magnetic moments μU ∼ 0.74 μB (at 2 K) aligned along the c-axis of the hexagonal crystal structure below Curie temperature TC = 48K. With the application of pressure, gradual decrease of both, TC and the saturated magnetic moment, has been observed up to pressures ∼ 6 GPa. This is followed by a sharp drop of magnetic moment and a sudden disappearance of the magnetic order at the pressure of 6.5 GPa, suggesting a first-order phase transition, as expected for a clean system. The low temperature power law dependence of the electrical resistivity shows distinct anomalies around the ∼ 6 GPa, consistent with the pressure evolution of the magnetic moment and the ordering temperature. The tricritical point of the UCoGa phase diagram is located at approximately ∼ 30K and ∼ 6GPa.
- Publication:
-
AIP Advances
- Pub Date:
- May 2017
- DOI:
- 10.1063/1.4976300
- arXiv:
- arXiv:1611.03276
- Bibcode:
- 2017AIPA....7e5712M
- Keywords:
-
- Condensed Matter - Materials Science
- E-Print:
- AIP Advances 7, 055712 (2016)