Electrical Probe Stations

We have two electrical probe stations that allow us to measure longitudinal and transverse resistances in Hall bar devices using a lock-in technique. In the first station, DUTs are mounted on a motorized rotation stage and electrically connected using a wire bonder. The DUT can be rotated 360° in any given plane between the poles of an electromagnet producing fields up to 2.3 Teslas.

The second station uses the same measurement principles as the first one but the DUTs are contacted using microprobes and we are able to apply field along two axes simultaneously (in-plane 0.3 T and out-of-plane 0.05 T).  

Setups are complemented with a constant ac/dc current source, a pulse generator (1-100 ns, -/+50V), a high voltage source (<1.1 kV), an arbitrary waveform generator, and a high speed advanced oscilloscope. 

Optical Probe Stations

We have two Magneto-optic Kerr Effect (MOKE) setups operating in wide-field (WF) and scanning laser (SL) modes, respectively. WF-MOKE allows us to image magnetic domains in ultrathin (0.5-50 nm) ferromagnetic films with perpendicular magnetic anisotropy with resolution down to 1 um^2. It is equipped with a blue LED source and a high-speed/resolution camera to capture magnetization dynamics in (quasi-)real-time.

SL-MOKE operates with a focused laser in a selected range of wavelengths (405-632 nm) and can probe the out-of-plane magnetization orientation locally (~1 um^2). The sample is mounted on a motorized x-y translation stage, which allows scanning the sample with high precision and mapping the magnetization orientation over a larger area (e.g., 30x30 um^2). 

Both setups are complemented with relevant current sources (ac/dc/pulse), enabling us to study current-driven magnetization dynamics. 

Thin Film Deposition Tool

We have a dual-chamber magnetron sputtering tool with dc and rf deposition capabilities. Chambers are dedicated to metal and oxide deposition, respectively, with a separate load lock chamber. We can deposit from two different targets simultaneously (co-deposition) in both chambers, and they can operate independently. Currently, the two chambers accommodate nine targets with a possibility of an upgrade up to seventeen. The oxide chamber has a gun for off-axis deposition, a unique feature to deposit stoichiometric films from multi-element targets. The sample holder can rotate, be heated (up to 850°C), and apply a transverse magnetic field of 20 mT on the substrate during the deposition. Both chambers work at a base pressure in the range of 5x10^8 Torr.