Magnetic Materials
PEEM Sample Environments
TEMPERATURE DEPENDENT MEASUREMENTS
Samples can be:
- cooled with liquid Nitrogen down to ~ 100 K with dedicated cartridges equipped with Pt100 temperature sensors and allowing internal temperature regulation loop.
- heated radiatively up to ~1000 K or flashed with e-beam up to ~1900 K for short periods. The temperature is measured either with a W/Re type C thermocouple spot-welded and in thermal contact with the rear face of the sample or with an optical pyrometer in the preparation chamber.
Real time imaging remains possible from ~100 K to 1000 K.
IN SITU AND IN OPERANDO MEASUREMENTS
The microscope operates using an high 15-20kV accelerating voltage applied between the sample surface and the first immersion lens at few mm distance. Any piece of electronic in contact with the sample cartridge must be located inside the high voltage (HV) rack and particular care must be taken to protect it from electrical discharges coming from the sample. Any additional equipment not already supplied by the beamline must be discussed with beamline staff well in advance.
The following in operando measurements can be performed, while imaging with PEEM:
- in-plane magnetic fields: < 40 mT in pulsed mode (no imaging) and < 2 mT in-operando
- out-of-plane magnetic fields: < 80 mT in pulsed mode and < 20mT in-operando
- out-of-plane electric fields produced by application of a bias between the sample surface and rear face (+/- 400 V).
Due to strong accelerating voltages, HV electrical sparks may occur at the surface and destroy samples. To limit their occurence on samples with patterned electrodes and sensitive channels, current pulses must be applied with the accelerating voltage switched off.
CARTRIDGES FOR IN SITU AND OPERANDO MEASUREMENTS
Cartridges for in-situ and in-operando measurements are listed below:
Magnetic Field Cartridges
- Magnetic field cartridges
Uniaxial in-plane (<40mT in pulsed mode) and out-of-plane (<80mT in pulsed mode) magnetic fields can be applied. Please contact beamlime staff for more information.
In-plane uniaxial (left) and out-of-plane, PCB compatible (right) magnetic field cartridges.
Electric Field/Low Temperature Cartridges
- Out-of-plane electric fields
The copper cartridges are optimised for cryogenic temperatures and mild annealings (100K < T < 400K). The pt100 thermoresistor accurately measure the sample temperature. The sample is mounted on an electrode that allows the application of out-of-plane electric fields (+/- 400V).
Out-of-plane electric field cartridge with temperature control (100K < T < 400K).
Current Pulsing Cartridges
- Current pulsing cartridges with wire bonded electrical contacts.
The standard version requires the sample to be glued on the cartridge and has four contact pillars as micro-bond contact pads (figure 1, left panel).The Printed Circuit Board (PCB) version, carries a PCB that can be separately used to micro-bond the sample.Both the standard and the PCB carriers allow 4 contacts to be made.
The tempearature-pulsing PCB cartridge has 2 contacts available for the sample. Temperature reading and control using a pt100 thermal sensor and a heating filament is possible in the range of 100-600K.
Omicron plate adaptor
- Samples mounted on Omicron flagplate (such as used for in-situ STM imaging) can be measured in the PEEM, using an cartridge adaptor.
PEEM cartriges with Omicron plate adaptor.
Additional Cartridges
- Cartridges combining different excitations are possible (details must be discussed with beamline staff).
ANCILLARY ELECTRONICS
In situ and in operando measurements are supported by full remote control of the following components:
- Synapse Multiplexing unit (4 channels)
- Keithley 2461 sourcemeter (I-V characteristics/hysteresis)
- Avtec pulse generator (10ns rise time)
- Two channel bipolar power supply for uniaxial and vectorial magnetic field cartridges
- Temperature controller for low temperature cartridges with bipolar high voltage source (+/- 400 V)
SAMPLE TRANSFER CAPABILITIES
- UHV Ferrovac suitcase
UHV suitcase (compatible with Omicron plates).
- Inert gas suitcase (transfer from glovebox)
Inert gas suitcase (compatible with Elmitec cartridges). The suitcase can be fitted inside a glovebox without the need of a docking port.
