Complete vertical M-H loop shift in La0.7Sr0.3MnO3/SrRuO3 thin film heterostructures

Abstract

In the current work, we have epitaxially integrated La0.7Sr0.3MnO3/SrRuO3 (LSMO/SRO) BLs with the technologically important substrate Si (100) using pulsed laser deposition. Interestingly, at 4 K, under the magnetic field sweep of ±1500 Oe, a complete vertical M-H loop shift is observed in the sample prepared with 180 nm SRO thickness, which is unusual. This vertical shift persists even up to a field sweep range of ±6000 Oe, at which point the shift disappears and a symmetrical hysteresis loop centered at the origin is observed. In contrast, at the same temperature, under the same field sweep range, we observe a normal M-H loop (no or little vertical shift) from the sample with 45 nm SRO thickness. In both the cases, the LSMO thickness was held constant at ∼100 nm. It appears that SRO moment is frozen in place in the latter case, providing a clear demonstration of the effect that biasing layer (SRO) thickness can have on the magnetic characteristics of bilayer films. We attribute this vertical shift to the strong interplay between the uniaxial magnetocrystalline anisotropy and microscopic interface domain structure.

Ferromagnetic oxide heterostructures on silicon

“…[14,[7][8][9][10][11] The spin magnetic moment of this sample is estimated at 1.2 µ B per Ru 4+ ion, consistent with previously reported values (1.1-1.6 µ B per Ru 4+ ion) for the bulk SRO thin films. As shown by the curve in red, the sample with only LCMO layer exhibits characteristic [4,5] T C at about 240 K. The saturation magnetization is estimated at 3.…”

“…As shown by the curve in red, the sample with only LCMO layer exhibits characteristic [4,5] T C at about 240 K. The saturation magnetization is estimated at 3. [6,[7][8][9][10][11] on relaxed SRO thin films. The M-H curve (in red) recorded from LCMO layer also reveals a clear saturation behavior characterized by H c of 625 Oe (see inset of Fig.…”

“…In these heterostructures interesting magnetic properties such as antiferromagnetic exchange coupling and its cross-over to ferromagnetic exchange coupling [7][8][9][10][11] have been identified. Despite the fact that La 0.7 Ca 0.3 MnO 3 (LCMO) shares similar electronic and magnetic properties with LSMO, there has been no report on the epitaxial growth and investigation of magnetic properties of LCMO when it is interfaced with SRO layer on any substrate.…”

Magnetic exchange coupling in bilayers of two epitaxial ferromagnetic oxides

“…We have grown La 0.7 Sr 0.3 MnO 3 /SrRuO 3 /SrTiO 3 (STO)/MgO/TiN/Si (1 0 0) heterostructures and optimized the growth conditions for each layer in this geometry. This work is facilitated by the deposition of an epitaxial TiN (a = 4.24 Å) layer, in which, three lattice plans of Si (a = 5.43 Å) match very well with four of TiN (a = 4.24 Å) and the epitaxial growth occurs via domain matching epitaxy (DME) [5][6][7][8]. Each layer in this heterostructure was grown epitaxially.…”

“…This selection of buffer layers made it possible to integrate epitaxial thin film of LSMO/SRO on Si(1 0 0). The prototype bilayers based on these oxides were thoroughly characterized with in-plane and out-of-plane XRD, TEM and STEM-Z techniques as reported [5] in our earlier work. The temperature-and magnetic-field dependent magnetization measurements were carried out using a Quantum design MPMS SQUID dc magnetometer with the sensitivity 610-8 emu at 0 T. The magnetic field is applied along [1 0 0] direction of the sample.…”