Titanium nitride (TiN) shows low resistivity at room temperature (27 mu Omega cm), high thermal stability and thus has the potential to serve as seed layer in magnetic tunnel junctions. High quality TiN thin films with regard to the crystallographic and electrical properties were grown and characterized by x-ray diffraction and 4-terminal transport measurements. Element specific x-ray absorption spectroscopy revealed pure TiN inside the thin films. To investigate the influence of a TiN seed layer on a ferro(i)magnetic bottom electrode in magnetic tunnel junctions, an out-of-plane magnetized Mn2.45Ga as well as in- and out-of-plane magnetized Co2FeAl thin films were deposited on a TiN buffer, respectively. The magnetic properties were investigated using a superconducting quantum interference device and anomalous Hall effect for Mn2.45Ga. Magneto optical Kerr effect measurements were carried out to investigate the magnetic properties of Co2FeAl. TiN buffered Mn2.45Ga thin films showed higher coercivity and squareness ratio compared to unbuffered samples. The Heusler compound Co2FeAl showed already good crystallinity when grown at room temperature on a TiN seed-layer. (C) 2015 AIP Publishing LLC

We investigated crystallographic and magnetic properties of TiN buffered Co2FeAl thin films. Room temperature deposition of the Heusler compound led to high crystalline ordering. The layer thickness and post annealing temperature dependence of the coercivity, squareness ratio, and the anisotropy constant of the thin Co2FeAl films were measured. High perpendicular magnetic anisotropy was observed for the 0.9 nm thin Co2FeAl film. A squareness ratio of one was reached at 325 °C post annealing temperature, which is lower compared to previous studies. It remained constant for temperatures up to 500 °C. Surface sensitive x-ray absorption and x-ray magneto circular dichroism measurements were carried out, in order to investigate the element specific magnetic moments. A magnetic moment of 5.4 ± 0.4 μB/f.u. for the 1 nm thin Co2FeAl was determined, which is in good agreement with the previously reported values for Cr or MgO buffered Co2FeAl.

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A new method is developed for the optimum design of inductors carrying unsymmetrical currents and having magnetically soft ferromagnetic cores biased with magnetically hard gaps. Techniques are given for obtaining designs to meet those specifications for which the optimum design has no air gap, and those specifications imposing limits on the maximum induction.

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