1. Spin Polarized Inelastic Neutron Scattering NIST Summer School on Neutron Spectroscopy Seung-Hun Lee Peter Gehring Sungil Park Alina Visinoiu Gokhan Caliskan Erick Lawson Martin Sulic Tessema Guebre Xabiher Kapil Gupta Jose Rodriguez Mike Lewis

2. O A B Edge-sharing octahedra  CW = -390 K T N = 12.5 K Corner-sharing tetrahedra (B sites) Magnetic Phase Transition in ZnCr 2 O 4 AFM H = -J  S i. S j All exchange interactions can not be satisfied. Magnetic frustration or ZnCr 2 O 4 -Space Group-Fm3d

3. SPINS Monochromator Sample Analyzer Single Detector Neutron Source Sample Flat Analyzer Position-Sensitive Detector 2i2i aa aiai Increased data acquisition Rate over conventional TAS By an order of magnitude.

4. Exploring Statics Q(Å -1 ) Intensity Q resolution~0.02 Å -1 Doubling of the unit cell (H,K,L)=(1,1,1) (1/2,1/2,1) (1/2,1/2,3/2)

5. Order Parameter

6. Exploring Dynamics

7. Inelastic Resonance Peak

8.  -Correlation Length T=15K>T N 0.6meV<E<1.4meV HWHM=  ~0.45Å  ~2.2Å T=1.5K<T N 4.2meV<E<1.4meV HWHM=  ~0.36Å  ~2.8Å

9. Summary SPINS probes both the static crystal and magnetic state of the system. SPINS probes the dynamic behavior of the system. SPINS is a relatively fast spectroscopy technique. SPINS is ideal for studying specific regions in Q-  space. Acknowledgements: NIST NSF NCNR