Low Temperature Low Temperature Measurements of Novel Measurements of Novel

Low-Dimensional SystemsLow-Dimensional Systems

James R. MaloneyJames R. Maloney

James M. StockJames M. Stock

What Are Low What Are Low Temperatures?Temperatures?

Room Temperature 300 K

Freezing Point of Water 273 K

Liquid Nitrogen 77 K

Liquid Helium 4 KOur Sample 1.5 K

Absolute Zero 0 K

So What are So What are Low-Dimensional Low-Dimensional

Systems?Systems?

1-D Chains1-D Chains

2-D Planes2-D Planes

How Can This Make the How Can This Make the World A Better Place?World A Better Place?

We want better high temperature We want better high temperature superconductorssuperconductors

High temperature superconductors High temperature superconductors have similar characteristics to low-have similar characteristics to low-dimensional systemsdimensional systems

If we’re going to make progress, we If we’re going to make progress, we need to understand these systems!need to understand these systems!

Highly EfficientVirtually Pollution Free

OutlineOutline

I. Reaching Low TemperaturesI. Reaching Low Temperatures

II. Our SamplesII. Our Samples

III. Properties Under InvestigationIII. Properties Under Investigation

IV. ResultsIV. Results

I. Reaching Low I. Reaching Low TemperaturesTemperatures

Designed a cell compatible with a Designed a cell compatible with a cryogenic probe to house our cryogenic probe to house our samplessamples

The probe could be chilled by The probe could be chilled by liquid nitrogen, liquid helium, and liquid nitrogen, liquid helium, and evaporative coolingevaporative cooling

The Sample CellThe Sample Cell

The Cryogenic ProbeThe Cryogenic Probe

Bridge Balancing MethodBridge Balancing Method

LabVIEW is Everywhere

Lock-InAmplifier

SignalGenerator(Internal) Sample

CapacitanceBridge

II. Our SamplesII. Our Samples

(CH(CH33))22NHNH22CuClCuCl33 ‘MCCL’ ‘MCCL’

II. Our SamplesII. Our Samples

Langmuir-Blodgett (LB) filmLangmuir-Blodgett (LB) film

III. Properties III. Properties Under InvestigationUnder Investigation

Search for phase transitions of MCCLSearch for phase transitions of MCCL

– By observing capacitanceBy observing capacitance

Look at the conductivity of LB filmLook at the conductivity of LB film

– Measuring conductance from the Measuring conductance from the capacitance signalcapacitance signal

IV. ResultsIV. Results

MCCL MCCL

IV. ResultsIV. Results

LB filmLB film

IV. ResultsIV. Results

Aluminum Aluminum

What Is Next?What Is Next?

Reproducibility of 154 K MCCL Reproducibility of 154 K MCCL transitiontransition

Search for second phase transition Search for second phase transition surrounding 10 Ksurrounding 10 K

Investigate possible noise coupling Investigate possible noise coupling between cavitiesbetween cavities

Questions?Questions?