Observation of spin glass behavior in chiral Mn48Fe34Si18 with a β -Mn related structure

Abstract

The ternary silicide system Fe-Mn-Si exhibits several complex magnetic phases and the chemical similarity of Fe and Mn enables these two elements to be mutually substituted over a wide compositional range. Because this substitution results in chemical disorder and often causes competing magnetic exchange interactions, frustrated spin glass ordering is expected to occur for some Fe-Mn-Si phases. However, the observation of a spin glass state within these alloys has been elusive to date. This paper reports magnetization and ac susceptibility measurements on Mn48Fe34Si18. The compound crystallizes in a Mn3IrSi-type structure, which is closely related to that of β-Mn. Typical spin glass behavior is observed at low temperatures. This comprises a bifurcation of field-cooled and zero-field-cooled magnetization, a displacement of the field-cooled hysteresis loop, magnetic relaxation, a memory effect, and a sharp, frequency-dependent cusp in the ac susceptibility at the freezing temperature. Mn48Fe34Si18 is demonstrated to be a canonical spin glass.