Irreversible metamagnetic transition and magnetic memory in small-bandwidth manganite Pr_1−xCa_xMnO₃(x= 0.0–0.5)

Abstract

The present paper reports detailed structural and magnetic characterization of the low-bandwidth manganite Pr(1-x)Ca(x)MnO(3) (with x = 0.0-0.5) (PCMO) polycrystalline samples. With increasing Ca content, reduction of the unit cell volume and improvement in perovskite structure symmetry was observed at room temperature. Magnetic characterization shows the signature of coexisting AFM-FM ordering and spin-glass phase at the low doping range (x = 0.0-0.2) while increased hole doping (x = 0.3-0.5) leads to charge ordering, training effect and an irreversible metamagnetic phenomenon. The large irreversible metamagnetism in the CO phase of PCMO and the corresponding spin memory effect is a direct consequence of hysteretic first-order phase transition arising from the weakening of the CO state under the external magnetic field and trapping of the spins due to a strong pinning potential in the material.

Optimization of Pr0.9Ca0.1MnO3thin films with varying in-situ oxygen annealing treatments

“…In spite of the tensile strain, the in-plane lattice parameters of the films are smaller than the bulk values (a = 5.451 Å, b = 7.662 Å and c = 5.572 Å [7]) indicating that the effect of oxygen is greater than the effect of tensile strain. It is also good to notice that due to the tensile strain by the substrate, the difference of the unit cell volume compared to bulk, ∆V , of PCMO is reduced.…”

“…The films with thickness of 100 nm were grown on (001) SrTiO 3 (STO) substrates by pulset laser deposition (PLD) technique from high purity PCMO target prepared by the solid state method [7]. The details of the deposition parameters are reported elsewhere [9].…”

“…The in-plane lattice parameters of the STO substrates are greater than those of bulk PCMO (d 101 = 3.897 Å [7] for the bulk, to be compared to 3.905 Å for the STO substrate) and thus the deposited films are under tensile strain. In spite of the tensile strain, the in-plane lattice parameters of the films are smaller than the bulk values (a = 5.451 Å, b = 7.662 Å and c = 5.572 Å [7]) indicating that the effect of oxygen is greater than the effect of tensile strain.…”

“…The increase in the Mn 4+ content also reduce the cooperative Jahn-Teller (JT) [14] distortion affecting the Mn 3+ ions, generating local JT distortion around the Mn 3+ ions [15]. This increases the ordering of PCMO crystal at the same time packing the atoms into a smaller volume [7].…”

“…These correlated electron materials have many intriguing properties, such as colossal magnetoresistance (CMR), rich magnetic phase diagram including charge-ordered (CO) phase [6], first order irreversible metamagnetic transition [7] and large magnetocaloric effect [8]. These different properties also give rise to a great technological potential in applications like magnetic field sensors, memory devices [6,10], magneto-optical devices, magnetic refrigeration and spintronic components [11].…”