The magnetic properties of transition metal clusters are a unique function of their size and differ from their bulk behavior due to quantum confinement. Here we show that surface modification provides another channel to tune their magnetic properties. This is demonstrated by taking Mn4 as an example. Although Mn4 carries a giant magnetic moment of 20 μB, the magnetic coupling can be tuned from ferromagnetic to ferrimagnetic by changing the number of gold atoms coated on its surface. We found that 26 gold atoms are needed to fully cover a Mn4 cluster. When partially coated, the system exhibits ferromagnetic coupling with a total magnetic moment of 18 μB and it becomes ferrimagnetic with a moment of 8 μB when fully coated. This magnetic cross-over is caused by the shrinking of the Mn-Mn bond length, suggesting that the magnetic properties of a Mn4 cluster can be tuned by controlling the surface coverage.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry