Subhash Kaushik

Ferromagnetism and metal-semiconducting transition in Fe-doped ZnO thin films

We report the room temperature ferromagnetism and a metal–semiconductor transition at 227 K in 200 MeV Ag15+-ion irradiated thin films of Fe-implanted ZnO. The single phase nature of Fe-doped ZnO after ion irradiation is confirmed by x-ray diffraction. Magneto-resistance measurements show spin polarization below 150 K. X-ray absorption spectroscopy and x-ray magnetic circular dichroism studies at room temperature reveal that Fe is oxidized in a mixed valence (Fe2+ and Fe3+) state and the magnetic signal is due to the Fe2+ state. The observations are explained on the basis of the combined effect of carrier doping by Fe3+ and oxygen vacancies.

Thermally activated current transport in MgB2 films

Thermally-activated flux flow (TAFF) resistivity above the irreversibility field is reported for two different c-axis textured MgB_2 superconducting films. Transport measurements at different perpendicular magnetic fields 0 < B < 9 T and temperatures from 5 to 40K reveal TAFF Ohmic resistivity described by the Arrhenius law with the quadratic field dependence of the activation energy. Our transport measurements on bulk MgB_2 ceramic samples also show the TAFF behavior, but do not show the quadratic field dependence of U(T,B). We explain our results in terms of thermally-activated drift of pre-existing quenched dislocations in the vortex lattice. Our results indicate that thermal fluctuations can be essential in determining the irreversibility field in MgB2 though to a much lesser extent than in high-temperature superconductors.

Neutron diffraction study of Bi doped cubic spinel Co2MnO4

Polycrystalline Bi doped spinel BixCo2-xMnO4 compounds were prepared by solid state reaction route. Room temperature neutron diffraction study reveals that all the compounds are formed in cubic phase and there is no change in the crystal structure due to Bi doping and the compound has cubic structure with Fd-3m space group. Cell parameter found to increase with respect to Bi doping and ferrimagnetic nature is established through magnetization. Low temperature neutron diffraction is carried out and emphasis the ferrimagnetic ordering in the samples of BixCo2-xMnO4 series.

Neutron diffraction, specific heat and magnetization studies on Nd2CuTiO6

Structural and physical properties of a double-perovskite compound, Nd2CuTiO6 have been studied using neutron diffraction, magnetization and specific heat measurements. The compound crystallizes in an orthorhombic structure in space group Pnma. The interesting observation we make here is that, though no long range magnetic order is observed between 2 and 300K, the low temperature specific heat and magnetic susceptibility behavior exhibits non-Fermi liquid like behavior in this insulating compound. The magnetization and specific heat data are presented and discussed in light of these observations.

A multicentric observational study to evaluate the role of homoeopathic therapy in vitiligo

Background: Vitiligo has an immense psychological impact on the affected individual and a reason for low self-esteem. Considering the disappointing outcomes, A multicentric open clinical study was undertaken by the Central Council for Research in Homoeopathy, at five institutes and units in India from October 2005 to September 2010. Aims and Objectives: This observational study aimed to see the usefulness of homoeopathic therapy in the management of vitiligo. Materials and Methods: 432 patients of all age groups suffering from vitiligo were enrolled in the study. Out of that, 169 patients completed 2 years of follow-up and were considered for analysis. Homoeopathic medicines, based on the totality of symptoms and repertorization were prescribed. The analysis of the cases was based on the Vitiligo Symptom Score (VSS) and photographs of the patients. Result was analyzed using statistical method of SPSS version 20. Results: The changes in the mean VSS at intervals of every 6 months was found to be statistically significant. Homoeopathic treatment was found to be useful in relieving vitiligo in varying degrees in 126 patients, out of which 4 (2.94%) cases showed marked improvement, 15 (11.03%) cases showed moderate improvement, 77 (56.62%) cases showed mild improvement, and 30 patients although improved, fell in the category of not significant improvement group (below 25% improvement). Ten homoeopathic medicines were found useful in the study of which Sulphur (n = 27), Arsenicum album (n = 19), Phosphorus (n = 19), and Lycopodium clavatum (n = 10) were the most commonly indicated and useful medicines.

Assessing the therapeutic usefulness of Ricinus communis: A multicentric observational clinical verification study

Introduction: Clinical verification is an ongoing research programme of the Central Council for Research in Homoeopathy, under which many symptoms of Indian and rarely used drugs in Homoeopathy have been clinically verified. Objectives: To clinically verify the symptomatology of Ricinus communis as observed during its proving conducted by Council and also to ascertain the clinical symptoms relieved in the process of verification. Materials and Methods: Two hundred and twenty-five patients from all age-groups and both sexes were enrolled from the outpatient departments (OPDs) of the institutes and units of the Council following the exclusion and inclusion criteria as per protocol and obtaining written consent. The presenting signs and symptoms were recorded in a predefined case recording proforma and if Ricinus communis was found very closely similar to the symptoms of the patient, the patients were enrolled in the study. The medicine was prescribed in different potencies as per the need of the case and in accordance with homoeopathic principles. The progress was noted in a follow-up sheet to determine the effects of the medicine, in relieving the symptoms of the patient. Result: Forty eight out of fifty three symptoms obtained from proving of Ricinus communis could be clinically verified. The characteristic indications were left-sided affinity, aggravation from sun, amelioration in open air, dryness of mucous membrane of gastrointestinal tract, dissatisfaction leading to irritability and anger. The usefulness of the medicine was mostly marked in relieving headache, coryza, aphthae, gastritis, diarrhoea, constipation and acne. All the verified symptoms indicated the scope of its therapeutic action. Conclusion: Ricinus communis can be considered as an important medicine for the management of acne, aphthae, backache, colic, constipation, coryza, cough, diarrhoea, dyspepsia, fever, gastritis, headache and irritability.