title: Polaron melting and ordering as key mechanisms for colossal resistance effects in manganites.
abstract: Polarons, the combined motion of electrons in a cloth of their lattice distortions, are a key transport feature in doped manganites. To develop a profound understanding of the colossal resistance effects induced by external fields, the study of polaron correlations and the resulting collective polaron behavior, i.e., polaron ordering and transition from polaronic transport to metallic transport is essential. We show that static long-range ordering of Jahn-Teller polarons forms a polaron solid which represents a new type of charge and orbital ordered state. The related noncentrosymmetric lattice distortions establish a connection between colossal resistance effects and multiferroic properties, i.e., the coexistence of ferroelectric and antiferromagnetic ordering. Colossal resistance effects due to an electrically induced polaron solid-liquid transition are directly observed in a transmission electron microscope with local electric stimulus applied in situ using a piezo-controlled tip. Our results shed light onto the colossal resistance effects in magnetic field and have a strong impact on the development of correlated electron-device applications such as resistive random access memory (RRAM).
authors: Institute of Materials Physics, University of Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen, Germany. jooss@ump.gwdg.de
authors: Ch
authors: Ch
authors: Jooss
authors: L
authors: L
authors: Wu
authors: T
authors: T
authors: Beetz
authors: R F
authors: RF
authors: Klie
authors: M
authors: M
authors: Beleggia
authors: M A
authors: MA
authors: Schofield
authors: S
authors: S
authors: Schramm
authors: J
authors: J
authors: Hoffmann
authors: Y
authors: Y
authors: Zhu
references: Nat Mater. 2004 Mar;3(3):164-70
references: 14991018
references: Phys Rev B Condens Matter. 1996 Oct 1;54(14):10001-10007
references: 9984736
references: Phys Rev Lett. 2003 Nov 28;91(22):227202
references: 14683268
references: Phys Rev Lett. 1993 Oct 4;71(14):2331-2333
references: 10054646
references: Nature. 2003 Nov 6;426(6962):55-8
references: 14603314
references: Inorg Chem. 2001 Apr 9;40(8):1978-80
references: 11312758
references: Phys Rev Lett. 2002 Aug 26;89(9):097205
references: 12190435
references: Phys Rev Lett. 2000 May 8;84(19):4489-92
references: 10990718
references: Nat Mater. 2004 Dec;3(12):853-6
references: 15558036
references: Phys Rev Lett. 2000 Jun 26;84(26 Pt 1):6086-9
references: 10991130
references: Nature. 2005 Nov 24;438(7067):474-8
references: 16306987
references: Phys Rev Lett. 1995 Mar 27;74(13):2587-2590
references: 10057965
references: Science. 1998 Jun 19;280(5371):1925-8
references: 9632388
references: Phys Rev B Condens Matter. 1996 Jan 15;53(4):R1689-R1692
references: 9983682