[Phys-seminars] 2017-12-04 Condensed Matter Seminar

dganit dganit at bgu.ac.il
Mon Nov 27 09:45:26 IST 2017

Condensed Matter Seminar

 DATE: 04-12-17

 TIME: 11:30

 PLACE: Physics building (#54) room 207

Non equilibrium states, relaxation, and noise in bulk and nano-sized strongly correlated electron systems

Barukh Dolgin, BGU

Strongly correlated electron systems (SCES) are materials, which cannot be described well in terms of independent electrons since the movement of one electron in SCES depends on the positions and movements of all other electrons. The prominent example of such systems are colossal magnetoresistive magnesium oxides called manganites. The ground state of SCES is a result of a detailed balance between the competing charge, lattice, orbit and spin degrees of freedom. Small distortion of the balance results to a complex collective behavior and the observed phenomena. Single crystals bulk and proton irradiated lithium doped nanowires, were probed using noise and transport measurements. A deeper insight into the nature of metastable resistivity states and intrinsic spontaneous tunnel junctions in manganite single crystals at low temperatures has been obtained. Transport and noise measurements demonstrated the feasibility of using conductivity noise investigations as a tool for an ins
 ight into the physics of charge transport in highly correlated manganite systems. For the nano sized manganites a magnetic relaxation measurements have been employed to get insight into the physical and magnetic structure of manganite nanoparticles. The measurements of intrinsic noise in microwires with defect induced magnetism and correlation of the noise properties with the distribution of hydrogen in the irradiated wires and with the electronic relaxation times opened new perspectives for using noise as a diagnostic and control tool in future investigations of complex oxides and, in particular, of defect induced magnetism. The obtained results gave several important inputs for theoretical modeling of the phenomena in highly correlated oxides, what will eventually provide future experimental work with better theoretical guidance.

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