Nature of the glassy magnetic state in the Cu2.84Mn0.44Al0.72 shape memory alloy
1 UGC-DAE Consortium for Scientific Research, Kolkata Centre, Sector III, LB-8 Salt Lake, Kolkata 700 098, India
2 Department of Solid State Physics, Indian Association for the Cultivation of Science 2 A & B Raja S. C. Mullick Road, Jadavpur, Kolkata 700 032, India
Received: 29 July 2013
Accepted: 21 November 2013
The magnetic ground state of the ferromagnetic shape memory alloy of nominal composition Cu2.84Mn0.44Al0.72 was investigated. The sample shows the reentry of a glassy magnetic phase below the martensitic transition temperature, which is found to have complex character with two distinct anomalies in the temperature-dependent ac susceptibility data. The sample retains its glassy phase even below the second transition as evident from the magnetic memory measurements in different protocols. Existence of two transitions along with their observed nature suggest that the system can be described by the mean-field Heisenberg model of reentrant spin glass as proposed by Gabay and Toulous. The sample provides a fascinating example where a Gabay-Toulous–type spin-glass state is triggered by a first-order magneto-structural transition.
PACS: 75.50.Lk – Spin glasses and other random magnets / 75.47.Np – Metals and alloys / 81.30.Kf – Martensitic transformations
© EPLA, 2013