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# Karapetrova Evguenia <jenia@anl.gov>
# requesting 5 days, at minimum=4 days
# beamline 33BM, Identifying Orbital Ordering in Digital Superlattice LaxSr1-xMnO3 Films.
# instrument 33BM-C fourc
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# top:/home/www/beamtime-requests/req01142.txt
# UNICAT Member Beam Time Request  #1142
# created Mon Apr 30 16:31:32 CDT 2007
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apsrun:
	2007-02

beamline:
	33BM

collaboration:
	No

collaborator_Jenia:
	ON

contact:
	jenia@anl.gov

days:
	5

description:
	Resonant multiple Bragg X-ray diffraction of the forbidden (10-4) reflection of LaMnO3 has been used to distinguish orbital ordering (OO) from typical Mn-O bond length disorder [1]. The difficulty arises as the OO is itself a bond length distortion. It is difficult to separate both effects experimentally, and the only difference is the sign of the resulting structure factor. However, interference between three-beam scattering and resonant scattering may determine the phase of the resonant scattering. Thus by measuring the azimuthal asymmetry of Mn resonant scattered multi beam reflections one can study the Mn orbital ordering effect decoupled from bond length disorder [2].

	Typically layered manganite films have their doping material randomly distributed, this causes a level of bond length disorder adversely affecting the characteristics of the films. In this proposal a series of digitally engineered LaxSr1-xMnO3 films have allowed the control and reduction of bond length disorder within the films [3]. By growing the samples layer by layer the Sr doping level is acquired by controlling the ratio SrO and LMO layers, in effect reducing the Mn-O bond length disorder. The increased structural order of the films is postulated to allow the Mn orbital ordering to occur.

	Electrical characteristics suggest that orbital ordering may occur but competing structural/bond length disorder renders it difficult to positively identify the existence of orbital ordering. This experiment aims to clarify whether these films exhibit orbital ordering and answer whether it correlates with the electrical characteristics and the large temperature dependent out of plane lattice expansions.

equipment_required:
	displex

experiment:
	Identifying Orbital Ordering in Digital Superlattice LaxSr1-xMnO3 Films.

foreign_nationals:
	

hazards:
	

instrument:
	33BM-C fourc

instrument_other:
	

minimumdays:
	4

name:
	Karapetrova Evguenia

nonmembers:
	Phillip Ryan

submit:
	Submit

unacceptable_dates:
	June22-Jyly 2, August 10 - August 22

z34ID_details:
	


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