Reentrant spin-glass state in a geometrical frustrated multiferroic system: Role of disorder

We investigated the effect of magnetic (Mn) and nonmagnetic (Ga) doping at the Cr site of the layered geometrically frustrated antiferromagnetic compound LiCrO2. 10% Ga doping at the Cr site does not invoke any metastability typical of a glassy magnetic state. However, similar amount of Mn doping drives the system to a spin glass (SG) state which is particularly evident from the magnetic memory and heat capacity studies. The onset of glassy state in 10% Mn doped sample is of reentrant type developing out of higher temperature antiferromagnetic state. The SG state in the Mn-doped sample shows a true reentry with the complete disappearance of the antiferromagnetic phase below the SG transition. The lack of SG state on Ga doping indicates the importance of random ferromagnetic/antiferromagnetic bonds for the glassy ground state in LiCrO2.