True reentry of the glassy state in geometrically frustrated LiCr(1-x)Mn(x)O(2)

TL;DR

This study demonstrates that Mn doping in LiCrO2 induces a true reentrant spin glass state, with the magnetic phase disappearing below the transition, unlike nonmagnetic Ga doping which does not induce glassiness.

Contribution

It reveals that magnetic Mn doping causes reentrant spin glass behavior in LiCrO2, highlighting the role of ferromagnetic bonds in the glassy state, unlike nonmagnetic doping.

Findings

Mn doping induces a reentrant spin glass state.

Ga doping does not produce a glassy magnetic state.

The spin glass state involves the disappearance of antiferromagnetic order.

Abstract

The development of spin glass like state in a geometrically frustrated (GF) magnet is a matter of great debate. We investigated the effect of magnetic (Mn) and nonmagnetic (Ga) doping at the Cr site of the layered GF 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 certainly drives the system to a spin glass state which is particularly evident from the relaxation, 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 spin glass state in the Mn-doped sample shows a true reentry with the complete disappearance of the antiferromagnetic phase below the spin glass transition. Mn doping at the Cr site can invoke random ferromagnetic Cr-Mn bonds in the otherwise 120 degree antiferromagnetic triangular lattice leading to the non-ergodic spin frozen state. The lack of spin glass state on Ga doping indicates the importance of random ferromagnetic/antiferromagnetic bonds for the glassy ground state in LiCrO2. Spin glass state in GF system has been earlier observed even for small non-magnetic disorder, and our result indicates that the issue is quite nontrivial and depends strongly on the material system concerned.