MnFe0.5Ru0.5O3: an above-room-temperature antiferromagnetic semiconductor
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99 GENERAL AND MISCELLANEOUS↗
Engineering topics
Padmanabhan, Haricharan
Publications and source records attributed to Padmanabhan, Haricharan.
Magnetostriction-Polarization Coupling in Multiferroic Mn2MnWO6
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99 GENERAL AND MISCELLANEOUS↗
Linear and nonlinear optical probe of the ferroelectric-like phase transition in a polar metal, LiOsO 3
LiOsO 3 is one of the first materials identified in the current literature as a “polar metal,” a class of materials that are simultaneously noncentrosymmetric and metallic. In this work, the linear and nonlinear optical susceptibility of LiOsO 3 is studied by means of ellipsometry and optical second harmonic generation (SHG). Robust optical birefringence is observed using spectroscopic ellipsometry. The nonlinear optical susceptibility extracted from SHG polarimetry reveals that the tensor components are of the same magnitude as in the isostructural insulator LiNbO 3 , except the component along the polar axis d 33 is suppressed by an order of magnitude. Temperature-dependent SHG measurements in combination with Raman spectroscopy indicate a continuous order-disorder type polar phase transition at 140 K. Linear and nonlinear optical microscopy measurements reveal 109°/71° ferroelastic domain walls, like in other trigonal ferroelectrics. No 180° polar domain walls are observed to emerge across the phase transition.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Adhesion at WC/diamond interfaces - A theoretical study
We investigate the adhesion at the interface of face-centered tungsten-carbide (001) and diamond (001) from density-functional calculations. Four high-symmetry model interfaces, representing different lattice orientations for either side of the interface, are constructed to incorporate different degrees of strain arising due to lattice mismatch. The adhesion, estimated from the ideal work of separation, is found to be in the range of 4 - 7 J m{sup −2} and is comparable to that of metal-carbide interfaces. Maximum adhesion occurs when WC and diamond slabs have the same orientation, even though such a growth induces large epitaxial strain at the interface. From electronic structure calculations, we attribute the adhesion to covalent interaction between carbon p-orbitals as well as partial ionic interaction between the tungsten d- and carbon p-orbitals across the interface.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗