Recent studies on weak ferromagnets Fe2-xMnxCrAl (0<x<1) reveal the presence of cluster glass (CG) and Griffiths phase (GP) below and above the ferromagnetic transition temperature (TC) [(2019) Sci. Rep. 9 15888]. In this work, the influence of these inhomogeneous phases on the critical behaviour (around TC) of the above-mentioned series of alloys has been investigated in detail. For the parent alloy Fe2CrAl, {\gamma} is estimated as ~ 1.34, which lies near to ordered 3D Heisenberg model, whereas obtained value of {\beta} ~ 0.273 does not belong to any universality class. With increment in Mn concentration, both exponents {\gamma} and \b{eta} increases, where {\gamma} and {\beta} approaches disordered 3D Heisenberg model and ordered 3D Heisenberg model, respectively. The observed deviation in {\gamma} and unconventional value of {\delta} can be ascribed to the increment in GP with Mn-concentration. The trend noted for {\beta} can be attributed to the increment in CG regime with an increase in Mn-content. The self-consistency and reliability of the estimated exponents are verified by the Widom scaling relation and scaling equations of state. Our studies indicate that the critical phenomenon of Fe2-xMnxCrAl (0<x<1) alloys possibly belong to a separate class and is not described within the framework of any existing universal model.
@article{arxiv.2012.09453,
title = {Unconventional critical behaviour in weak ferromagnets Fe2-xMnxCrAl (0<x<1)},
author = {Kavita Yadav and Dheeraj Ranaut and K. Mukherjee},
journal= {arXiv preprint arXiv:2012.09453},
year = {2021}
}