Muon Spin Relaxation/Rotation Studies of Novel Magnetic Systems

Muon spin relaxation/rotation is a powerful technique for probing magnetism in materials. As a real space probe, the muon complements neutron scattering's reciprocal space sensitivity. Muons probe magnetic fluctuations in a frequency window between inelastic neutron scattering and nuclear magnetic resonance. In this presentation I will describe our recent work on geometrically frustrated materials including the pyrochlore lattice compounds Yb$_{\mathrm{2}}$Ti$_{\mathrm{2}}$O$_{\mathrm{7}}$, Gd$_{\mathrm{2}}$Pt$_{\mathrm{2}}$O$_{\mathrm{7}}$, NaCaNi$_{\mathrm{2}}$F$_{\mathrm{7}}$ and others. I will also discuss $\mu$ SR's volume fraction sensitivity as applied to the transition from hidden order to antiferromagnetism in heavy fermion U(Ru$_{\mathrm{1-x}}$Fe$_{\mathrm{x}})_{\mathrm{2}}$Si$_{\mathrm{2}}$ and U(Ru$_{\mathrm{1-x}}$Os$_{\mathrm{x}})_{\mathrm{2}}$Si$_{\mathrm{2}}$.