Multiple magnetic phase transitions with different universality classes in bilayer La$$_{1.4}$$Sr$$_{1.6}$$Mn$$_{2}$$O$$_7$$ manganite

Abstract

Here, we report three magnetic transitions at 101 K (T$$_{C1}$$ C 1 ), 246 K (T$$_{C2}$$ C 2 ) and 295 K (T$$_{C3}$$ C 3 ) in bilayer La$$_{1.4}$$ 1.4 Sr$$_{1.6}$$ 1.6 Mn$$_{2}$$ 2 O$$_7$$ 7 . 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$$_{C1}$$ C 1 , T$$_{C2}$$ C 2 and T$$_{C3}$$ C 3 have been studied by MAPs and Kouvel–Fisher method. Based on these analyses four magnetic phases are: (1) 2D Ising ferromagnetic (FM) below T$$_{C1}$$ C 1 ,(2) 2D Heisenberg canted antiferromagnetic (CAFM-I) and FM clusters in temperature range T$$_{C1}$$ C 1 < T < T$$_{C2}$$ C 2 , (3) 2D Heisenberg CAFM-II and FM clusters with non magnetically interacting planes in temperature range T$$_{C2}$$ C 2 < T < T$$_{C3}$$ C 3 and (4) paramagnetic for T > T$$_{C3}$$ C 3 .

Above-Room-Temperature Ferromagnetism in Thin van der Waals Flakes of Cobalt-Substituted Fe5GeTe2

“…The bimodal behavior is consistent with the existence of two-phase transitions. While we do not have a definitive explanation for what is the cause of this double-phase transition, we do point out that multiple phase transitions and the corresponding multimodal M vs. T (which our (ΔB) 2 vs. T measurement provides a proxy as) is known in the literature, e.g., in bilayer La 1.4 Sr 1.6 Mn 2 O 7 54 and even in van der Waals magnet CrI 3 . 55,56 In the work ref 55, three transitions were observed, which are attributed to an interplay of structural and magnetic transitions.…”

Evidence of a Large Refrigerant Capacity in Nb-Modified La1.4Sr1.6Mn2−xNbxO7 (0.0 ≤ x ≤ 0.15) Layered Perovskites

“…Each sample represents two transition temperatures (T C ), one below 100 K (transition 1) and the other located above room temperature (transition 2). These transition points individually represent the magnetic contribution of each structural phase for which the FM-PM transition in the low temperature region is allotted to the LSMO R-P phase [32], and T C values towards room temperature correspond to the other perovskite phase [30]. Upon Nb substitution, each of the transition points abruptly shifted towards the low temperature region from 80 K to 60 K and 370 K to 308 K, respectively.…”

Structural and Thermoelectric Properties of Gd2−2xSr1+2xMn2O7 Double-Layered Manganites

“…During the course of our systematic research on the phase diagram of the Gd–Sr–Co/Mn–O systems [ 22 , 23 ], a Gd 2−2 x Sr 1+2 x Mn 2 O 7 solid solution was found. Our magnetic measurements of the Gd 2−2 x Sr 1+2 x Mn 2 O 7 samples in the temperature range of 2–350 K under an applied magnetic field of 0.02 T show two ferromagnetic transitions, which is in analogy to the temperature-dependent magnetizations of La 1.2 Sr 1.8 Mn 2 O 7 [ 24 ] and La 1.4 Sr 1.6 Mn 2 O 7 [ 25 ]. In this paper, we report the structural and TE properties of double-layered manganites Gd 2−2 x Sr 1+2 x Mn 2 O 7 ( x = 0.5, 0.625, 0.75).…”