Established in fall 2000, the Penn State MRSEC Central Facilities Laboratory (CFL) is housed in Davey Laboratory, which is located on Penn State University Park Central Campus within a 10 minute walk of the academic departments of the Center participants. It currently focuses on advanced cryogenic characterization, including PPMS and SQUID capabilites. This includes a multimode atomic force microscopy (AFM)/magnetic force microscopy (MFM) / scanning tunneling microscopy (STM) system, two superconducting quantum interference device (SQUID) magnetometers for magnetization measurements over a temperature range of 2K-1000K, three physical property measurement systems (PPMS) for magneto-transport measurements over a temperature range from 50 mK - 400 K and magnetic fields from 0 - 9 T.
Two Nikon TE2000 optical microscopes are currently in use by MRSEC members for materials characterization and dynamic motors experiments. Both are configured with fluorescence and differential interference contrast capabilities and connected to CCD cameras and monitors. One microscope, housed in Hallowell building, is used extensively for biological motor experiments and is being outfitted with an optical tweezer for measuring and manipulating motor proteins and nanoparticles.
We have designated space in the MRSEC CFL for an Acton Research TriplePro triple spectrometer and a Princeton Instruments Spec-10:100BR detector. The TriplePro spectrograph will be coupled to the existing CLF Pulsed Spectra-Physics Nd:YAG 250 Series laser. This Nd:YAG laser is combined with an Optical Parametric Oscillator (OPO) tunable from 450 nm up to 1.8 µm. The energy per pulse in this range is in the order of few tens of mJ, and the YAG laser itself can be used as a powerful (hundreds of mJ) laser source for each of its lines.
The Leiden refrigerator has a base temperature of approximately 0.013K, and a maximum magnetic field up to 9T. This system is equipped with many leads for standard transport measurements, a low temperature coaxial cable for high frequency measurement, and capillary for cryogenic liquid experiments. Researchers in the MRSEC have used this system for heat capacity and transport measurements on superconducting and metallic nanowires.
We have developed a system to fabricate porous alumina membranes with pore size of 10-100 nm and metallic nanowires with lengths of 10-50 µm. The system contains a dc voltage supply (0-60 V, 0-2A), a multimeter, anodizing bath and depositing cell, cooling bath, heating plate and stirring plate. High quality single-crystal metallic nanowires (Au, Ag, Cu, Sn, Pb, Bi and Zn) are fabricated by controlling the deposition parameters (temperature, applied electric potential, etc.). Polycrystalline (Rh, Pt, Co, Ni) or striped nanowires (Co/Cu) are also achieved.
Used to study the mechanical properties of nanoscale PZT cantilevers. The system consists of a small ion-pumped vacuum chamber with controlled leak back that is mounted onto the stage of a Nikon inverted microscope in the MRSEC CFL. This will allow chips with many cantilevers to be studied under ambient pressures ranging from atmospheric to 10-9 torr. Long working distance microscope objectives are used to focus a laser beam onto the oscillator through a viewport.
The Omicron GMBG Near-Field Optical Microscope (NSOM) with Atomic Force attachment is capable of optical and topographical measurements. It can measure optical fields with a 100 nm resolution, which is well under the diffraction limit of the conventional counterparts. During the acquisition process the NSOM measures the topography of the area of interest as well. The resolution in this mode is few nm in lateral and sub-nanometer in vertical direction.
Although a broad-based instrument, MRSEC researchers mainly use this system to do transport measurements on superconducting and silicon nanowires. Electrical transport and heat capacity measurements can be carried out from 400 K down to 0.45 K and under fields as high as 9 T. The system includes an integrated, multi-channel, dc resistance bridge, calibrated thermometry, and software algorithms for measuring heat capacity.
The upgraded Thermionics VE-90 thermal evaporator is a versatile 3 source thermal evaporation system that has been used to deposit a variety of thin metal films to support electrical and optical characterization efforts within the MRSEC. The evaporator has a turbo-molecular pumping system, a stainless steel bell-jar with removable top plate, two 2kVA dc power supplies for three independent resistive sources, two thickness/rate controllers, and a pneumatic source shutter.
This workstation includes a Coherent Ar+ 351-nm continuous wave laser source, which is used to record information in UV sensitive polymers. This source is coupled to an optical set-up designed for creating 1-, 2-, and 3-D interference patterns with periods of less than 0.5 µm. It is currently being used to pattern a variety of materials including commercially available photoresists and polymer dispersed liquid crystals.
MRFN.org is supported by the MRSEC Program of the National Science Foundation. Image in the header is courtesy of CRISP MRSEC.
