Funded by the National Science Foundation
Our initial efforts focused on the behavior
of elemental magnets, such as Ni, Fe, and Co. Our current research in this
area centers on a rare earth metal, gadolinium. Gadolinium is particularly
interesting because of its unique magnetic properties. Gadolinium metal
atoms have a very large spin magnetic moment of 7/2 and the bulk Curie
temperature is 293 K, right near room temperature. Initial magnetic measurements
on the Gd samples reveal that there may be independent contributions to
the magnetic properties from the gadolinium clusters and from the interphase
atoms between the clusters. We will also be studying the effect of grain
size on the magnetic properties by varying the grain sizes of the samples
we make. In the future, we will expand our effort into understanding the
properties of two component magnets to investigate exchange-coupled systems
and systems of a magnetic cluster in a non-magnetic matrix.
The TEM image shows Gd clusters made by Dave Schmitter using this deposition source. The length bar is 50 nm.
Our initial efforts focused on the behavior of elemental magnets, such as Ni, Fe, and Co. Our current research in this area centers on a rare earth metal, gadolinium. Gadolinium is particularly interesting because of its unique magnetic properties. Gadolinium metal atoms have a very large spin magnetic moment of 7/2 and the bulk Curie temperature is 293 K, right near room temperature. Initial magnetic measurements on the Gd samples reveal that there may be independent contributions to the magnetic properties from the gadolinium clusters and from the interphase atoms between the clusters. We also will study the effect of grain size on the magnetic properties by varying the grain sizes of the samples we make. In the future, we will expand our effort into understanding the properties of two component magnets to investigate exchange-coupled systems and systems of a magnetic cluster in a non-magnetic matrix.
The cluster deposition system is shown below. The large chamber on the left is for deposition, with the sputter source at the far left. The smaller chamber at the right is for in-situ compaction.
The structures
made by this system are primarily multi-phase structures. For Gd, this may include hcp and/or fcc Gd, and GdN. Annealing can be used in
some cases to produce single-phase samples. Among the interesting effects we have observed are room-temperature ferromagnetism, exchange
coupling between phases, and magnetically glassy behavior.