Salvatore Perna Tutor: Prof. Claudio Serpico XXIX Cycle -I year presentation Nanomagnetism and Spintronics

Salvatore Perna.  I AM A GRADUATE STUDENT IN ELECTRICAL ENGINEERING  … AND AS A PHD STUDENT I’M WORKING ON NANOMAGNETISM AND SPINTRONICS

Salvatore Perna. Nanomagnetism and Spintronics  Study the evolution of the magnetic properties of the ferromagnetic materials on nanometric scale, in presence of external excitations such as magnetic field or spin-polarized currents  This study involves many theoretical fields : Nonlinear dynamical systems Chaos theory Statistical mechanics Stochastic processes Solid state physics, and so on…  … and is of technological interest for applications regarding :  Magnetic Recording ( optimized memory devices)  Information and Comunication Technologies ( oscillators, magnetic logic circuits,…)

Salvatore Perna. MY RESEARCH ACTIVITIES :  Reliability of ultrafast ( sub-nanosecond) switching strategies Control of switching probability Probability to reach desidered state Controlling field Phase-Flow Interpretation of Magnetization Relaxation in Nanomagnets G.Bertotti, ID Mayergoyz, M d'Aquino, S Perna, C Serpico Magnetics, IEEE Transactions on 50 (11), 1-4, 2014

Salvatore Perna. MY RESEARCH ACTIVITIES :  Reliability of ultrafast ( sub-nanosecond) switching strategies Proposed Novel switching strategies Analysis of Reliable Ultrafast Precessional Switching in the Presence of Transverse Applied Magnetic Fields M d'Aquino, S Perna, C Serpico, G Bertotti, ID Mayergoyz Magnetics, IEEE Transactions on 50 (11), 1-4, 2014 With exciting magnetic field With injected spin-polarized current Analysis of reliable sub-ns spin-torque switching under transverse bias magnetic fields M d'Aquino, S Perna, C Serpico, G Bertotti, ID Mayergoyz Magnetics, accepted for publication in the Journal of Applied Physics.

Salvatore Perna. MY RESEARCH ACTIVITIES :  Assisted switching strategy Study the effects of the application of microwave excitation Progressive Basin erosion due to a very low amplitude external microwave excitation close to the calculated threshold value  Heteroclinic tangle phenomena in nanomagnets subject to time-harmonic excitations, C. Serpico, A.Quercia, S. Perna, G.Bertotti, M. d’Aquino and I.D. Mayergoyz, accepted for publications on Journal of Applied Physics.

Salvatore Perna. MY RESEARCH ACTIVITIES :  Assisted switching strategy Study the interaction of the magnetic system and the thermal fluctuation due to the finite temperature of the external enviroment Dependence of the switching fields from the temperature fo the external bath  Noise-induced bifurcations in magnetization dynamics of uniaxial nanomagnets Noise-induced bifurcations in magnetization dynamics of uniaxial nanomagnets C Serpico, S Perna, G Bertotti, M d'Aquino, A Quercia, ID Mayergoyz Journal of Applied Physics 117 (17), 17A709, (2015) Astroid Field-Temperature Normalized values of Temperature

Salvatore Perna. MY RESEARCH ACTIVITIES :  Low energy dissipations devices Study the switching condition for a compensated anisotropy nanomagnet ( in collaboration with the University of Messina, local reference Prof. Giovanni Finocchio ) The spin-polarized current necessary to activate switching dynamics is one order of magnitude lower. SWITCHING PROPERTIES OF PERPENDICULAR STT- MRAMs WITH SECOND ORDER ANISOTROPY S. Perna, R. Tomasello, C. Serpico, M. d’Aquino, and G. Finocchio, accepted for presentation for poster presentation at the Intermag 2015 conference.

Partecipation to Conference 1.Oral presentation of the work : Phase-Flow Interpretation of Magnetization Relaxation in Nanomagnets in IEEE International Magnetics Conference, Dresden ( Germany), May 4-8 ( 2014)Phase-Flow Interpretation of Magnetization Relaxation in Nanomagnets 2.Poster presentation of the work : Phase-Flow Interpretation of Magnetization Relaxation in Nanomagnets in ET2014, XXX Riunione Annuale dei Ricercatori in Elettrotecnica, June (2014), Sorrento ( Italy).Phase-Flow Interpretation of Magnetization Relaxation in Nanomagnets 3.Oral Presentation of the work : Noise-induced bifurcations in magnetization dynamics of uniaxial nanomagnets in Magnet 2015, the 4 th italian conference on magnetism, Bologna (Italy), February 17-19, (2015).Noise-induced bifurcations in magnetization dynamics of uniaxial nanomagnets 4.Poster presentation of the work : Analysis of reliable sub-ns spin-torque switching under transverse bias magnetic fields, in Magnet 2015, the 4 th italian conference on magnetism, Bologna (Italy), February 17-19, (2015). Salvatore Perna.

SUMMARY OF THE FIRST YEAR ACTIVITIES Credits year Estimated bimonth Summary Modules Seminars Research

Salvatore Perna. SECOND YEAR ACTIVITIES PLAN I.From 1° April to 31 July i will work at the University of Salamanca with Prof. Luis Lopez Diaz and doctor Eduardo Martinez ( Department of Applied Physics) on the dynamics of coupled multidimensional magnetic structures ( magnetic vortices ). II.Modules Ad Hoc : 24 Credits Elettromagnetismo e Relatività ( Prof. Amedeo Capozzoli) Dinamica Non Lineare I e II ( Prof. Claudio Serpico e Prof. Mario Di Bernardo) Complementi di Analisi Funzionale ( Prof. Renato Fiorenza) Micromagnetics ( Prof. Claudio Serpico ) III.Seminars : 5 Credits IV.Teaching Activity : 10 Credits V.Research Activities : 45 Credits

Salvatore Perna.