A new stress dilatometer, and measurement of the thermal expansion under uniaxial stress of Mn₃Sn

We present new a new device for measuring the thermal expansion of materials under tunable uniaxial stress. We have performed first measurements on Mn₃Sn - a room temperature antiferromagnet (AFM) that exhibits a spontaneous Hall effect [1]. Measurement of thermal expansion provides thermodynamic data about the nature of phase transitions, and uniaxial stress provides a powerful tuning method that does not introduce disorder. Mn₃Sn exhibits an anomaly in its thermal expansion near ~270 K, associated with a first order change in the magnetic structure. We show that this transition temperature is suppressed under uniaxial compression along the c-axis. These results show the efficacy of our stress-dilatometer as well as provide new, thermodynamic insight into the response to applied stress of Mn₃Sn.

[1] Satoru Nakatsuji, Naoki Kiyohara, and Tomoya Higo, Nature 527, 212–215 (2015)