UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore-452001, India.
J Phys Condens Matter. 2010 May 5;22(17):176002. doi: 10.1088/0953-8984/22/17/176002. Epub 2010 Apr 7.
We present our study of the effect of substrate induced strain on La(5/8-y)Pr(y)Ca(3/8)MnO(3) (y = 0.45) thin films grown on LaAlO(3), NdGaO(3) and SrTiO(3) substrates that show large scale phase separation. It is observed that unstrained films grown on NdGaO(3) behave quite similarly to bulk material but the strained films grown on SrTiO(3) show melting of the insulating phase to the metallic phase at low temperatures. However, the large scale phase separation and metastable glass-like state is observed in all the films despite differences in substrate induced strain. The measurements of resistivity as a function of temperature under a cooling and heating in unequal field (CHUF) protocol elucidate the presence of a glass-like metastable phase generated due to kinetic arrest of the first order transformation in all the films. Like structural glasses, these magnetic glass-like phases show evidence of devitrification of the arrested charge order antiferromagnetic insulator (CO-AFI) phase to the equilibrium ferromagnetic metallic (FMM) phase with isothermal increase of magnetic field and/or iso-field warming. These measurements also clearly show the equilibrium ground state of this system to be FMM and the metastable glass-like phase to be AFI phase.
我们研究了衬底诱导应变对在 LaAlO3、NdGaO3 和 SrTiO3 衬底上生长的 La(5/8-y)Pr(y)Ca(3/8)MnO3（y = 0.45）薄膜的影响，这些薄膜表现出大规模的相分离。研究结果表明，在 NdGaO3 上生长的未应变薄膜与体材料表现得非常相似，但在 SrTiO3 上生长的应变薄膜在低温下会将绝缘相熔化成金属相。然而，尽管衬底诱导应变存在差异，但在所有薄膜中都观察到了大规模的相分离和亚稳玻璃态。在不等场冷却和加热（CHUF）协议下测量电阻随温度的变化，阐明了由于所有薄膜中一级相变的动力学停滞，产生了亚稳玻璃相。与结构玻璃一样，这些磁性玻璃相显示出由于被捕获的电荷有序反铁磁绝缘（CO-AFI）相的失稳，向平衡铁磁金属（FMM）相转变的迹象，这伴随着磁场的等温增加和/或等场升温。这些测量还清楚地表明，该系统的平衡基态为 FMM，亚稳玻璃相为 AFI 相。
