Noise as a mesoscopic probe of the colossal magnetoresistance effect

Robert D. Merithew; Akilan Palanisami; Frank M. Hess; Michael B. Weissman

doi:10.1117/12.488908

9 May 2003 Noise as a mesoscopic probe of the colossal magnetoresistance effect

Robert D. Merithew, Akilan Palanisami, Frank M. Hess, Michael B. Weissman

Proceedings Volume 5112, Noise as a Tool for Studying Materials; (2003) https://doi.org/10.1117/12.488908
Event: SPIE's First International Symposium on Fluctuations and Noise, 2003, Santa Fe, New Mexico, United States

Abstract

Epitaxial thin films and bulk crystals of the colossal magnetoresistance (CMR) material La_2/3Ca_1/3MnO₃ (LCMO) exhibit large discrete equilibrium resistance fluctuations in the region of phase space where the magnetoresistance effects are strongest. Strongly inhomogeneous current paths allow us to observe the random telegraph signals of individual mesoscopic regions of material fluctuating between the paramagnetic-semiconductor phase and the ferromagnetic-conductor phase. Temperature and field dependences of the Boltzmann factors of individual fluctuators yield measurements of the magnetic moment and entropy differences between these phases, and of the fluctuator volumes. These measurements provide some of the first quantitative thermodynamic information about the locally-homogeneous CMR phase transition in an otherwise strongly inhomogeneous system. Careful analysis of the field- and temperature-dependences allows us to discriminate between fluctuations across the (first-order) CMR phase boundary and fluctuations of magnetic domain orientation deep in the ferromagnetic state. Similar measurements of the closely-related CMR material La_2/3Sr_1/3MnO₃ (LSMO) show almost no noise associated with the CMR transition, consistent with a second-order phase transition in this material.

Citation Download Citation

Robert D. Merithew, Akilan Palanisami, Frank M. Hess, and Michael B. Weissman "Noise as a mesoscopic probe of the colossal magnetoresistance effect", Proc. SPIE 5112, Noise as a Tool for Studying Materials, (9 May 2003); https://doi.org/10.1117/12.488908

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
8 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Cardiovascular magnetic resonance imaging

Resistance

Magnetism

Crystals

Temperature metrology

Thermodynamics

Transition metals

Show All Keywords

Keywords/Phrases

Search In:

Publication Years