Mukes Kapilashrami

Transition from ferromagnetism to diamagnetism in undoped ZnO thin films

We report a systematic study of the film thickness dependence (0.1-1 mu m) of room-temperature ferromagnetism in pure magnetron-sputtered ZnO thin films wherein a sequential transition from ferroma ...

Room temperature ferromagnetism in pristine MgO thin films

Robust ferromagnetic ordering at, and well above room temperature is observed in pure transparent MgO thin films (<170 nm thick) deposited by three different techniques. Careful study of the wid ...

Experimental evidence for ferromagnetism at room temperature in MgO thin films

Ferromagnetic ordering at room temperature (RTFM) in MgO thin films deposited by RF magnetron sputtering under various atmospheric conditions and temperatures is reported. A saturation magnetization (M(S)) value as high as 1.58 emu g(-1) is (0.046 μB/unit cell) observed for a 170 nm film deposited at RT under an oxygen pressure of 1.3 × 10(-4) mbar. In contrast, films deposited at elevated temperature (under an identical oxygen pressure), or at higher oxygen pressures, as well as under a nitrogen atmosphere at RT show significantly suppressed magnetization. The ferromagnetic order in the MgO matrix is believed to be defect induced.

Ferromagnetism in ZnO co-doped with Mn and N studied by soft x-ray magnetic circular dichroism

We have investigated the electronic structure of ZnO:Mn and ZnO:Mn,N thin films using x-ray magnetic circular dichroism (XMCD) and resonance-photoemission spectroscopy. From the Mn 2p -> 3d XMCD ...

Ferromagnetism above room temperature in nickel–tetracyanoethylene thin films

Room temperature ferromagnetic ordering is reported in Ni–tetracyanoethylene (TCNE) thin films fabricated on Au substrates using physical vapor deposition (PVD) under ultra high vacuum conditions. This technique enables the preparation of very clean films without having any kind of contamination from oxygen-containing species, solvents or precursor molecules. Film stoichiometry was obtained from X-ray photoelectron spectroscopy (XPS) measurements. XPS derived stoichiometry points to a ∼1 : 2 ratio between Ni and TCNE resulting in Ni(TCNE)x, x ≈ 2. No evidence of pure Ni metal in the in situ grown films was present in the XPS or the ultraviolet photoelectron spectroscopy (UPS) measurements within the detection limits of the techniques.

Electronic structure of room-temperature ferromagnetic Mg1-xFexOy thin films

We present herein a soft x-ray spectroscopy study on the electronic and magnetic properties of Mg1-xFexOy thin films. A distinct shoulder feature on the absorption edge reflecting the unoccupied ox ...

Effect Of Synthesis Techniques On The Magnetic Properties Of Mn‐Doped ZnO

Mn‐doped ZnO thin films have been prepared using three different routes, namely, magnetron sputtering technique, Pulsed Laser Deposition technique using targets from powders synthesized by solid state, and chemical method. Films deposited using sputtering technique in absence of nitrogen pressure gives higher magnetic moment per Mn atom, than is the case with films prepared by PLD indicating that ferromagnetism in the DMS systems is highly sensitive to processing conditions.

Soft X-Ray Spectroscopy and Electronic Structure of 3d Transition Metal Compounds in Artificial Photosynthesis Materials

The surge to address the most pressing energy-related concerns has brought together researchers from different disciplines to common platforms of joint forces, which has led to significant advancements in the field materials science and in the development of new and improved analytical techniques for in situ studies of matter at atomic level with high precision. This chapter presents an overview on the role of transition metal elements in the field of energy research, and their contribution towards realization of efficient and sustainable photoelectric materials. In addition, this section also outlines the importance (as well as recent development) of synchrotron based X-ray spectroscopy technique (in the soft X-ray range) in the evaluation of transition metal complexes at nanoscale by reflecting over recent studies on the local chemical environment, charge symmetry, and charge transfer therein as a function of e.g. particle size (in nanoparticles) and/or impurity level (in doped systems).

On the defect induced ferromagnetic ordering above room-temperature in undoped and Mn doped ZnO thin films

Evidence for long range ferromagnetic order above room-temperature, RTFM, in pristine ZnO, In2O3, TiO2 nanoparticles and thin films, containing no nominal magnetic elements have been reported recen ...