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The magnetic domain structure, magnetic properties, and thermal stability of IrMn biased top spin valves containing Co and NiFe have been investigated. The magneto-optical indicator film pictures of Ni–Fe biased IrMn spin valve show the formation and motion of domain walls that separate large domains in the free film unlike the Co biased IrMn spin valve structure with many small microdomains. From the angular dependence of the ferromagnetic resonance linewidth (ΔH) and resonance field (Hres) it was found that the IrMn biased Co film is very different from the behavior of a NiO biased Permalloy film which exhibits two-magnon scattering. To investigate the thermal stability two kinds of magnetoresistance measurements at anneal temperature (TAnn) and room temperature (TRT) following anneals were accomplished.

We have built a variable temperature scanning probe microscope (SPM) that covers 4.6 K-180 K and up to 7 T whose SPM head fits in a 52 mm bore magnet. It features a temperature-controlled sample stage thermally well isolated from the SPM body in good thermal contact with the liquid helium bath. It has a 7-sample-holder storage carousel at liquid helium temperature for systematic studies using multiple samples and field emission targets intended for spin-polarized spectroscopic-imaging scanning tunneling microscopy (STM) study on samples with various compositions and doping conditions. The system is equipped with a UHV sample preparation chamber and mounted on a two-stage vibration isolation system made of a heavy concrete block and a granite table on pneumatic vibration isolators. A quartz resonator (qPlus)-based non-contact atomic force microscope (AFM) sensor is used for simultaneous STM/AFM operation for research on samples with highly insulating properties such as strongly underdoped cuprates and strongly correlated electron systems.

Molecular dynamics of hydrogen molecules trapped in micro-cavity between atomic-scale tip and VOPc molecules on surface and intermolecular interactions have been studied by using scanning tunneling spectroscopy and atomic force microscopy at atomic-scale.