Title: Manipulation of magnetic anisotropies for micro-magnetic device applications
Speaker: Dr. Tuhin Maity, Tyndall National Institute, Cork, Ireland
Abstract: Nano-structured magnetic materials are being investigated due to their unique properties and promising application opportunities. Applications of these materials are based on the ability to control magnetic anisotropies. In the present series of work the ability to control magnetic anisotropies by creating unique magnetic nano-structures of various ferromagnetic materials has been demonstrated. Different rotational symmetries of magnetic anisotropy were achieved in nano-modulated thin films due to dipolar interactions depending on modulation geometry. Such nano-modulated films were prepared by cost effective nano-imprint lithography process. Further approach was to investigate controllable exchange anisotropy or exchange bias in nano-composite materials for additional functionality. Large exchange bias was observed in the composite multiferroic material. In similar metal alloy composite thin film, competition between two different anisotropies results into direct observation of Inverted Hysteresis Loop (IHL). The IHL and non-IHL formation in such materials with very low coercivity and large positive exchange anisotropy/exchange bias results into increased energy product (BHmax) of the materials. Four remanence states can be achieved due to the co-existence of IHL and non-IHL in the same materials. There is a huge scope to integrate such nanostructured materials into various micro-magnetic device applications, e.g. high density magnetic memory, energy harvesting, magnetic sensor, etc.
Ref:
1. T Maity, S P Li, L Keeney and S Roy; Physical Review B 86 (024438), 71, (2012)
2. T Maity, S Goswami, D Bhattacharya and S Roy; Physical Review Letters 110 (10), 1072011, (2013)
3. T Maity, D Kepaptsoglou, Q Ramasse and S Roy Physical Review B-Rapid Communication, 95 (10), 100401 (2017)
4. T Ghoshal, T Maity, JF Godsell, S Roy and MA Morris; Advanced Materials 24 (18), 2390-2397, 7, (2012)