Mixed Magnetic Correlations in FeRh Films Laura H. Lewis, Northeastern University, DMR 0908767

1. Au FeRh (50 nm) MgO Mixed Magnetic Correlations in FeRh FilmsLaura H. Lewis, Northeastern University, DMR 0908767 Thin films of the magnetostructural com-pound FeRh have been confirmed to exhibit magnetic behavior significantly different from that of the bulk phase, attesting to the very strong role of strain in magnetic phase selection. This feature is anticipated to allow tailoring of the magnetic response for specific applications. Recent results obtained from high temp-erature SQUID (superconducting inter-ference device) magnetometry fromn 50-nm FeRh films capped with 2 nm of Au exhibit very unusual Curie (TC) transition behavior: the paramagnetic TC is 100 degrees lower than the ferromagnetic TC. This result indicates the unexpected presence of both ferro- and antiferro-magnetic correlations persisting to high temperature. Figure 1: FeRh thin film schematic showing 2-nm Au cap on a 50-nm FeRh film synthesized by sputter deposition. Figure 2: Results from high temperature SQUID magneto-metry of a 50-nm FeRh film. This experiment was conducted from 300-780 K in a 0.1 T field and shows a paramagnetic Tc ~572 K while the ferromagnetic Tc ~660 K.

2. Mixed Magnetic Correlations in FeRh FilmsLaura H. Lewis, Northeastern University, DMR 0908767 The collaborative culture was firmly established between Northeastern University and University of Leeds, UK, during the first year of this Materials World Network grant. Particularly notable aspects of this project are the participation of women in all aspects of the collaboration, the use of large scientific facilities and the involvement of undergraduate co-op students. The project was kicked off at the 2010 Joint INTERMAG-MMM Meeting (Washington DC, January 18–21) and was followed by experiments carried out at the National Synchrotron Light Source in March, April and August 2010. Four international video conferences were held between March and August 2010, and the research team presented a poster at the XRMS-10 Meeting (June 10-11, Diamond Light Source, Oxfordshire, UK). After the XRMS-10 meeting, Ms. Melissa Loving spent 10 days at the University of Leeds to deposit thin film samples and carry out a variety of sample characterization techniques in the laboratory of Prof. Chris Marrows. Melissa Loving (Ph.D. student), Chris Marrows (U. Leeds) and Mark DeVries (U. Leeds) adjust the diffractometer at X22C at the NSLS Alex Steele (co-op student), Melissa Loving and Laura Lewis (NU) take a break from collecting data at NSLS Beamline U4B.