The ac-magnetic susceptibility and dielectric response of complex spin ordering processes in Mn 3 O 4

Subhash Thota (1, 2, 3) , Kiran Singh (2) , Sanjib Nayak (1) , Ch. Simon (2) , Jitendra Kumar (3) , Wilfrid Prellier (2)

1 IIT Guwahati - Indian Institute of Technology Guwahati
2 CRISMAT - Laboratoire de cristallographie et sciences des matériaux
3 IIT Kanpur - Indian Institute of Technology Kanpur

We report a meticulous study of the ac-magnetization dynamics (χac(T)), relative dielectric permittivity εr(T), and magneto-dielectric (Δεr/εr(H)) response of various complex magnetic transitions that occur below the ferrimagnetic Néel temperature TN of Mn3O4. Besides the known sequence of transitions at TN ∼ 42.75 K, T1 ∼ 39 K, and T2 ∼ 34 K, the existence of a new anomaly reported recently at 38 K (T*) has been successfully probed by χac(T) and εr(T) measurements. The effect of external dc-bias fields (HDC) and driving frequency (f) on the above mentioned transitions has been investigated in consonance with the εr(T) and Δεr/εr(T,H) results. For the first time, we observed a clear hysteresis of about 5.15 K in the zero-field εr(T) across the incommensurate-to-commensurate transition T2 ∼ 34 K, which provides evidence to the first-order nature of this transition. The Arrott plot (H/M vs. M2) criterion has been used to distinguish the nature of all the sequential transitions that take place below TN.

Domaines: Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]; Supraconductivité [cond-mat.supr-con]; Electrons fortement corrélés [cond-mat.str-el]; Science des matériaux [cond-mat.mtrl-sci]

Subhash Thota, Kiran Singh, Sanjib Nayak, Ch. Simon, Jitendra Kumar, et al.. The ac-magnetic susceptibility and dielectric response of complex spin ordering processes in Mn 3 O 4. Journal of Applied Physics, 2014, 116 (10), pp.103906. ⟨10.1063/1.4895054⟩. ⟨hal-01954034⟩