Simultaneous enhancements of polarization and magnetization in epitaxialPb(Zr0.52Ti0.48)O3/

Abstract

Layered films of Pb(Zr 1-x Ti x )O 3 (PZT) and La x Sr 1−x MnO 3 (LSMO) are well-known multiferroic systems that show promise for numerous applications including data storage devices and spintronics. In this work, structure-property relationships are explored in novel PZT/CoFe 2 O 4 (CFO)/LSMO heterostructures with optimized ferroic properties. High quality, epitaxial PZT/CFO/LSMO heterostructures with the thickness of the CFO layer varying from 0 nm to 50 nm were grown on SrTiO 3 (100) substrates using an optimized pulsed laser deposition technique. An ultrathin (10 -20 nm) CFO layer was found to simultaneously improve the ferromagnetic and ferroelectric characteristics of the system through distinct mechanisms. The increase in magnetization and magnetic coercivity in the CFO-containing samples was associated with a tetragonal distortion of the CFO lattice under epitaxial strain, while perpendicular anisotropy generated by the distortion stabilized an out-of-plane orientation of the easy axis of magnetization in the thinnest CFO layers. Trapped charge at the CFO/PZT interface in PZT/CFO/LSMO induced an internal built-in field in the heterostructures, resulting in the accumulation of higher switched charges during voltage cycling and enhanced polarization in the samples over PZT/LSMO. An increase in electric coercivity was also observed in the CFOcontaining heterostructures, and is discussed in terms of a dielectric/FE layered capacitor model. Above a critical thickness, ~ 50 nm, the presence of a CFO layer has a negative effect on both magnetization and polarization in PZT/CFO/LSMO as compared to PZT/LSMO.

Enhancement of the Electrical Properties in BaTiO3/PbZr0.52Ti0.48O3 Ferroelectric Superlattices

“…Figure shows the P – E hysteresis loops of the BTO/PZT superlattices and the pure PZT and BTO thin films measured at 1 kHz and room temperature. The saturation polarizations ( P s ) of the pure PZT and BTO thin films are about 66 and 21 μC/cm 2 , respectively, which are comparable with those reported by the most previous works on the high-quality epitaxial films. , The values of remanent polarization ( P r ), P s , and coercive field ( E c ) values of the BTO/PZT superlattices are about 41 μC/cm 2 , 17.1 μC/cm 2 , and 230 kV/cm, respectively. The value of P r is smaller than that of the PZT film ( P r ≈ 47 μC/cm 2 ) but is larger than that of the BTO film ( P r ≈ 13 μC/cm 2 ).…”

“…The lattice mismatching between them is very small (∼1.0%), much less than that between the BaTiO 3 and SrTiO 3 in the BaTiO 3 /SrTiO 3 superlattices (∼2.3%). ,, This allows us to prepare the high-quality ferroelectric superlattices with a minimum of structural defects in the interfaces. Another reason is that the values of spontaneous polarization are about 20 μC/cm 2 and over 60 μC/cm 2 for the (001)-oriented BTO and PZT films, , respectively, so that there is a large polarization mismatch between them. Therefore, the BTO/PZT superlattices may be expected as an appropriate system to study the effect of polarization coupling.…”

Enhanced ferroelectric polarization in epitaxial(Pb1−xLax)(Mukherjee1, Hordagoda2, Pesquera3 et al. 2017Phys. Rev. BSelf Cite18010View full textAdd to dashboardCite

“…PZT has high mechanical and chemical stability allowing its safe encapsulation for device fabrication and the Pb in PZT is stable in the oxide form. PZT thin films and nanostructures are used in sensors, actuators, field-emitters, high-frequency electrical components, tuneable microwave circuits [8][9][10][11][12][13][14] and have also been proposed for use in magneto-electric (ME) memories and in electrocaloric solid-state coolers [15][16][17][18][19][20]. Realization of novel device applications and improvement of the existing technologies have thus created a constant demand for high quality PZT thin films exhibiting enhanced polarization properties.…”

Magnetically controlled space charge capacitance at La1−xSrxMnO3/SrxLa1−xTiO3 interfaces

“…The possibility of stabilizing new phases at the epitaxial interfaces between dissimilar complex oxides has attracted great research interest in recent years not only for its fundamental importance, but also for the exciting opportunities of new functionalities and device architectures . A large variety of unexpected interface phenomena has already been discovered like a two‐dimensional electron gas between LaAlO 3 and SrTiO 3 epitaxial layers , conventional metallicity between non‐metals and super‐conductivity between non‐superconducting oxides .…”