Mr Zhengqiang Yang
Email: firstname.lastname@example.orgTelephone: 0207 882 6572Room Number: G.O. Jones Building, Room 223
1st Supervisor: Dr Alan Drew
2nd Supervisor: Dr Anthony Phillips
Project Title: Low dimensional magnetism in the multiferroic metal-organic frameworks and lanthanide single molecular magnets.
The magnetic and crystallographic properties in a series of multiferroic metal-organic frameworks (MOFs) are studied. These perovskite structured family include metal guanidinium formates ([C(NH2)3]M(HCOO)3 , MGFs) and (di)methylammonium metal formates ([(CH3)2NH2]M(HCOO)3, DMMFs or [CH3NH3]M(CHOO)3, MAMFs), where M=Mn, Fe, Co, Ni, Cu, etc.
Unlike the other perovskites, the copper complexes (both CuGF and DMCuF) crystallise in the polar space group Pna21, as a result of the Jahn-Teller distortion (JTD) about the Cu2+ orbitals. Most interestingly, CuGF exhibits quasi-1D spin correlations even above the Neél temperature (4.6 K). We have studied using inelastic/quasi-elastic neutron scattering to reveal the spontaneous magnon decay regarding the exitations along the S=1/2 antiferromagnetic (AFM) Heisenberg chain.
A family of lanthanide single ion molecular magnets (CP*-RE-COT) are studied. We have demonstrated significant correlations even up to room temperature, using both magnetometry and muon spin spectroscopy. It is suggested that the magnetic couplings are antiferromagnetic with weak ferromagnetic component, though the spin structures need to be further investigated.
Examples of research funding:
China Scholarship Council (CSC)
S Han, Z Yang, et al., Spin Correlations in a quasi-1D Antiferromagnetic Heisenberg Chain, ready for submission (2018)