The innovation engine for new materials

Xiaolin Hu

Xiaolin Hu




Mount Holyoke College


Phillip Barton

Faculty Sponsor(s): 

Professor Ram Seshadri

Faculty Sponsor's Department(s): 


Project Title: 


Project Description: 

The search for and development of ferromagnetic semiconductors has received significant attention due to the potential impact multifunctional materials may have on technology. However, such a task is not trivial as possessing a band gap and exhibiting long range ferromagnetic order are properties that are often contraindicated. While most research has focused on the prototypical dilute magnetic semiconductor (Ga,Mn)As, the area of oxides is much less explored. Oxides have fundamentally different structures that may enable strong coupling of dilute spins in a host lattice. Sr1-xNaxCu2O2 was prepared with x = 0, 0.04, 0.1, and 0.2 in order to oxidize Cu from d10 Cu1+ to d9 Cu2+. This dopes the sample, creating unpaired spins and mobile hole carriers that we hypothesize will increase electrical conductivity and give rise to magnetic order. Samples were prepared by conventional ceramic processing and phase purity was identified by powder x-ray diffraction. Variable temperature electrical resistivity measurements were performed to verify doping and monitor a potential metal-insulator transition. Magnetic measurements were used to observe the magnetic ordering under different temperatures. Preliminary measurements confirm that Sr1-xNaxCu2O2 is diamagnetic and resistive. We speculate that with increased dopant of Na, Sr1-xNaxCu2O2 will transition from being an insulator to a metal, and from a diamagnetic to a ferromagnetic material. We hope this study will give new insights on developing multifunctional materials with a wide electrical band gap and ferromagnetic ordering.