#################################################### # Aaron Gray # requesting 5 days, at minimum=4 days # beamline 33BM, Observation of Temperature Dependent Phase Separation by X-ray Diffraction Measurements of the Colossal Magneto Resistive Material LPCMO # instrument 33BM-C fourc #################################################### # top:/home/www/beamtime-requests/req01169.txt # UNICAT Member Beam Time Request #1169 # created Fri Aug 24 17:02:35 CDT 2007 #################################################### apsrun: 2007-03 beamline: 33BM collaboration: Yes contact: ajgray@uiuc.edu days: 5 description: This is the same as GUP-8589 however the experiment could be done on 33BM as well as 33ID Bulk manganites are known to have 3 competing phases near the insulator to metal transition, which are the charge ordered insulating phase (COI), paramagnetic insulating phase (PMI) and ferromagnetic metallic phase (FMM). These different phases form domains of size ~ 5µm as observed by transmission electron microscopy [1]. These different phases have different lattice constants mainly due to Jahn-Teller distortion[2-4]. However, in thin films, strain, which is induced due to lattice constant mismatch between the substrate and film, can stabilize a different ground state from that of the bulk compound, e.g. in the case of a LPCMO film grown on a NdGaO3 substrate, the COI phase may be suppressed due to the slight tensile strain. However for thicker films relaxation of the substrate induced strain will occur and the properties of the film are expected to become like those of the bulk. Even though magnetization measurements and magnetic force microscopy images on these films support this scenario, direct structural evidence is needed to prove this phenomenon conclusively [5]. We propose to carry out x-ray diffraction experiments to observe the temperature dependence of the lattice constants for various film thicknesses. From the temperature dependence of the x-ray data, we hope to determine the effect of substrate induced strain on the COI phase. equipment_required: displex experiment: Observation of Temperature Dependent Phase Separation by X-ray Diffraction Measurements of the Colossal Magneto Resistive Material LPCMO foreign_nationals: Sung Hee Yun hazards: instrument: 33BM-C fourc instrument_other: minimumdays: 4 name: Aaron Gray nonmembers: Amlan Biswas, Sung Hee Yun submit: Submit unacceptable_dates: z34ID_details: #REMOTE_HOST: uni165.uni.aps.anl.gov #REMOTE_ADDR: 164.54.216.165 #CONTENT_LENGTH: 1970 #HTTP_REFERER: http://www.uni.aps.anl.gov/admin/unireq.html #HTTP_USER_AGENT: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.6) Gecko/20070725 Firefox/2.0.0.6