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Magnetic excitations in novel metal-organic quantum materials and molecular magnets

English title Magnetic excitations in novel metal-organic quantum materials and molecular magnets
Applicant Krämer Karl
Number 117817
Funding scheme Project funding (Div. I-III)
Research institution Departement für Chemie, Biochemie und Pharmazie Universität Bern
Institution of higher education University of Berne - BE
Main discipline Condensed Matter Physics
Start/End 01.01.2008 - 31.12.2010
Approved amount 407'664.00
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Keywords (8)

Magnetic excitations; spin clusters; single molecule magnets; quantum phase transitions; Bose-Einstein condensation; neutron scattering; single molecule magnet; metal-organic materials

Lay Summary (English)

Lay summary
We are using both elastic and inelastic neutron scattering to study elementary magnetic excitations in spin clusters and novel low-dimensional metal-organic systems with competing magnetic interactions and fascinating quantum phases:

Project A: Collective quantum states and quantum phase transitions in novel low-dimensional metal-organic spin systems: During recent years there has been a resurgence of interest in strongly correlated quantum systems, driven by a combination of breakthroughs in confined ultra-cold atom research, new and remarkable chemical compounds, and the desire to exploit such systems as a resource for quantum computing and as versatile atomic laboratories to study fundamental phases of matter. We have identified an almost unique realisation of the latter in a family of highly promising metal-organic materials towards the end of our last funding period. Based on our knowledge and the successful investigation of quantum criticality in the three-dimensional dimer materials TlCuCl3 and NH4CuCl3 we intend to study both the magnetic and electronic degrees of freedom in such custom-built metal-organic quantum magnets with their unprecedented internal (chemical) and external (magnetic field and hydrostatic pressure) tunability. Thus, we are going to apply neutron scattering and bulk experimental techniques to investigate the fundamental and intrinsic quantum mechanical properties of matter.

Project B: Spin dynamics in molecular magnets: Molecular magnetism remains at the forefront of research in magnetism. It brings together the fields of chemical synthesis by design, fundamental, and applied quantum physics. Building on our experience in crystal synthesis and inelastic neutron scattering, we propose two lines of research: i) Applying new neutron scattering methods to the Mn4Br-cluster, an archetypical axially anisotropic molecular magnet. The specific plans include order-of-magnitude improved resolution measurements using the new MARS spectrometer at SINQ, momentum resolved mapping of the wave-functions, transverse field tuning of the tunneling, and pumped stroboscopic techniques. Our efforts will simultaneously provide new insights into Mn-clusters and demonstrate new possibilities for general molecular magnetism research. ii) Studies of a new class of spin-1/2 molecular clusters. We intend to study isolated and coupled tri- and tetra-nuclear copper clusters. The coupled systems are a natural extension of our research in collective spin-dimer physics.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants


Associated projects

Number Title Start Funding scheme
132877 Magnetic Excitations in Low-Dimensional Arrays of Quantum Spins 01.01.2011 Project funding (Div. I-III)
121397 Sub-Kelvin high sensitivity magnetometer for magnetic materials exploration 01.07.2008 R'EQUIP
140862 Quantum Frustration in Model Magnets 01.07.2012 Project funding (Div. I-III)
128724 Purchase of a single crystal X-ray diffractometer for high resolution and accurate studies on molecular crystals 01.12.2009 R'EQUIP
130522 Quantum Magnetism - Dimer Physics and Dipolar Criticality 01.04.2010 Project funding (Div. I-III)
121898 Dimer Physics - from new Quantum Phases to Superconductivity 01.01.2009 Project funding (Div. I-III)
105175 Magnetic excitations in low-dimensional compounds of transition metal ions 01.01.2005 Project funding (Div. I-III)
172659 New materials for honeycomb-lattice and single-ion magnets 01.08.2017 Project funding (Div. I-III)
127126 NMR/NQR studies of strongly correlated electron systems 01.10.2009 Project funding (Div. I-III)
133815 Setup for studies of quantum phenomena in condensed matter systems at ultra-low temperatures in magnetic vector fields 01.04.2012 R'EQUIP