High pressure ultrasonic study of the Néel transition in a Cr + 3.0 at% Al alloy single crystal

Abstract

The pressure dependence of the commensurate spin density wave to paramagnetic Néel transition temperature ( T N) of a Cr + 3.0 at% Al alloy single crystal is determined from sound velocity measurements. T N varies linearly with pressure giving d T N/d P = −(370 ± 10) K GPa −1. The value of |d T N/d P| for the Cr + 3.0 at% Al alloy single crystal is among the largest recorded values for dilute Cr alloys with a second order CSDW-P phase transition. A value of d T N/d P calculated from bulk modulus and thermal expansion data by using a thermodynamic model, compares well with the directly measured result.