Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userImaging of Strain Driven Magnetic Domains and Strong Spin-Phonon Coupling in Epitaxial Thin Films of SrRuO3
81
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
Epitaxial thin films of SrRuO3 with large strain disorder were grown using pulsed laser deposition method which showed two distinct transition temperatures in Magnetic measurements. For the first time, we present visual evolution of magnetic domains across the two transitions using Magnetic force microscopy on these films. The study clearly showed that the magnetic anisotropy corresponding to the two transitions is different. It is observed that the perpendicular magnetic anisotropy is dominating in films which results in domain spin orientation preferably in out of plane direction. The Raman studies showed that the lattice is highly influenced by the magnetic order. The analysis of the phonon spectra around magnetic transition reveals the existence of strong spin-phonon coupling and the calculations resulted in spin-phonon coupling strength ({lambda}) values of {lambda} ~ 5 cm-1 and {lambda} ~ 8.5 cm-1, for SrRuO3 films grown on LSAT and SrTiO3 single crystal substrates, respectively.
rate research
Read More
Berry curvature plays a crucial role in exotic electronic states of quantum materials, such as intrinsic anomalous Hall effect. As Berry curvature is highly sensitive to subtle changes of electronic band structures, it can be finely tuned via external stimulus. Here, we demonstrate in SrRuO3 thin films that both the magnitude and sign of anomalous Hall resistivity can be effectively controlled with epitaxial strain. Our first-principles calculations reveal that epitaxial strain induces an additional crystal field splitting and changes the order of Ru d orbital energies, which alters the Berry curvature and leads to the sign and magnitude change of anomalous Hall conductivity. Furthermore, we show that the rotation of Ru magnetic moment in real space of tensile strained sample can result in an exotic nonmonotonic change of anomalous Hall resistivity with the sweeping of magnetic field, resembling the topological Hall effect observed in non-coplanar spin systems. These findings not only deepen our understanding of anomalous Hall effect in SrRuO3 systems, but also provide an effective tuning knob to manipulate Berry curvature and related physical properties in a wide range of quantum materials.
Enhanced magnetic moment and coercivity in SrRuO3 thin films are significant issues for advanced technological usages and hence are researched extensively in recent times. Most of the previous reports on thin films with enhanced magnetic moment attributed the high spin state for the enhancement. Our magnetization results show high magnetic moment of 3.3 Bohr-magnetron/Ru ion in the epitaxial thin films grown on LSAT substrate against 1.2 Bohr-magnetron/Ru ion observed in bulk compound. Contrary to the expectation the Ru ions are found to be in low spin state and the orbital moment is shown to be contributing significantly in the enhancement of magnetic moment. We employed x-ray absorption spectroscopy and resonant valance band spectroscopy to probe the spin state and orbital contributions in these films. The existence of strong spin-orbit coupling responsible for the de-quenching of the 4d orbitals is confirmed by the observation of the non-statistical large branching ratio at the Ru M2,3 absorption edges. The relaxation of orbital quenching by strain engineering provides a new tool for enhancing magnetic moment. Strain disorder is shown to be an efficient mean to control the spin-orbit coupling.
We report the observation of spin-glass-like behavior and strong magnetic anisotropy in extremely smooth (~1-3 AA) roughness) epitaxial (110) and (010) SrRuO3 thin films. The easy axis of magnetization is always perpendicular to the plane of the film (unidirectional) irrespective of crystallographic orientation. An attempt has been made to understand the nature and origin of spin-glass behavior, which fits well with Heisenberg model.
We show that using epitaxial strain and chemical pressure in orthorhombic YMnO3 and Co-substituted (YMn0.95Co0.05O3) thin films, a ferromagnetic response can be gradually introduced and tuned. These results, together with the measured anisotropy of the magnetic response, indicate that the unexpected observation of ferromagnetism in orthorhombic o-RMnO3 (R= Y, Ho, Tb, etc) films originates from strain-driven breaking of the fully compensated magnetic ordering by pushing magnetic moments away from the antiferromagnetic [010] axis. We show that the resulting canting angle and the subsequent ferromagnetic response, gradually increase (up to ~ 1.2degree) by compression of the unit cell. We will discuss the relevance of these findings, in connection to the magnetoelectric response of orthorhombic manganites.
Epitaxial strain in 4d ferromagnet SrRuO3 films is directly linked to the physical properties through the strong coupling between lattices, electrons, and spins. It provides an excellent opportunity to tune the functionalities of SrRuO3 in electronic and spintronic devices. However, a thorough understanding of the epitaxial strain effect in SrRuO3 has remained elusive due to the lack of systematic studies. This study demonstrates wide-range epitaxial strain control of electrical and magnetic properties in high-quality SrRuO3 films. The epitaxial strain was imposed by cubic or pseudocubic perovskite substrates having a lattice mismatch of -1.6 to 2.3% with reference to bulk SrRuO3. The Poisson ratio, which describes the two orthogonal distortions due to the substrate clamping effect, is estimated to be 0.33. The Curie temperature (TC) and residual resistivity ratios of the series of films are higher than or comparable to the highest reported values for SrRuO3 on each substrate, confirming the high crystalline quality of the films. A TC of 169 K is achieved in a tensile-strained SrRuO3 film on the DyScO3 (110) substrate, which is the highest value ever reported for SrRuO3. The TC (146-169 K), magnetic anisotropy (perpendicular or in-plane magnetic easy axis), and metallic conduction (residual resistivity at 2 K of 2.10 - 373 {mu}{Omega}cm) of SrRuO3 are widely controlled by epitaxial strain. These results provide guidelines to design SrRuO3-based heterostructures for device applications.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
