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| thermalcond:start [2013/11/06 11:51] – janet | thermalcond:start [2020/03/06 09:04] (current) – external edit 127.0.0.1 | ||
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| - | Ram and I tried nickel heaters on tetrahedrite w/ MnS insulating layer; the nickel reacted with the underlying film during dep, resulting in unusable heaters. In principle, Ni would be better than Al for 3-omega measurements as it has a significantly higher electrical resistivity and temperature coefficient of resistance. | + | Ram and I tried nickel heaters on tetrahedrite w/ MnS insulating layer; the nickel reacted with the underlying film during dep, resulting in unusable heaters. |
| + | In principle, Ni would be better than Al for 3-omega measurements as it has a significantly higher electrical resistivity and temperature coefficient of resistance. | ||
| Ram and I made another attempt with Al heaters on tetrahedrite films before I left. The films were extremely rough post-anneal, | Ram and I made another attempt with Al heaters on tetrahedrite films before I left. The films were extremely rough post-anneal, | ||
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| * Contact pads act as heat sinks! This causes a non-uniform temperature profile across the heater. A few papers have shown that this is not as big of a problem for AC signals above 10 Hz. However, using a heater design that moves the voltage leads away from the contact pads can help to get rid of this problem. Comsol modeling has shown that the voltage leads do not significantly alter the temperature profile of the heater. | * Contact pads act as heat sinks! This causes a non-uniform temperature profile across the heater. A few papers have shown that this is not as big of a problem for AC signals above 10 Hz. However, using a heater design that moves the voltage leads away from the contact pads can help to get rid of this problem. Comsol modeling has shown that the voltage leads do not significantly alter the temperature profile of the heater. | ||
| * The width of the heater needs to be extremely uniform for accurate measurements. For film measurements, | * The width of the heater needs to be extremely uniform for accurate measurements. For film measurements, | ||
| + | * FIXME Information about making masks for heater KAI please add | ||
| ==== Automation ==== | ==== Automation ==== | ||
