Multiple magnetic phase transitions with different universality classes in bilayer La$$_{1.4}$$Sr$$_{1.6}$$Mn$$_{2}$$O$$_7$$ manganite
Birendra Kumar, Jeetendra Kumar Tiwari, Harish Chandr Chauhan, Subhasis Ghosh
Abstract
Here, we report three magnetic transitions at 101 K (T[Formula: see text]), 246 K (T[Formula: see text]) and 295 K (T[Formula: see text]) in bilayer La[Formula: see text]Sr[Formula: see text]Mn[Formula: see text]O[Formula: see text]. The second order phase transitions have been identified at these transition points with the help of change in entropy analysis and modified Arrott plots (MAPs). The critical behavior around T[Formula: see text], T[Formula: see text] and T[Formula: see text] have been studied by MAPs and Kouvel-Fisher method. Based on these analyses four magnetic phases are: (1) 2D Ising ferromagnetic (FM) below T[Formula: see text],(2) 2D Heisenberg canted antiferromagnetic (CAFM-I) and FM clusters in temperature range T[Formula: see text] < T < T[Formula: see text], (3) 2D Heisenberg CAFM-II and FM clusters with non magnetically interacting planes in temperature range T[Formula: see text] < T < T[Formula: see text] and (4) paramagnetic for T > T[Formula: see text].