7400-S Options and Accessories

74035 single-stage variable temperature option

The single stage variable temperature assembly allows you to take measurements from 100 K to 950 K using LN₂, nitrogen, and argon gas. A single point measurement can be taken at 78 K. Only one hardware device is required to go from high to low temperatures, eliminating the need to remove or resaddle your sample. This ensures accurate measurements throughout the full scale temperature range. Rapid cool down from 950 K to room temperature and from room temperature to 100 K provides efficiency and high throughput. Like our full suite of variable temperature options, the single stage variable temperature assembly is mechanically isolated from the magnetometer head and sample, minimizing noise floor. Designed to deliver superior thermal performance, the unit’s vacuum insulation prevents freeze over at low temperatures and can operate safely at high temperatures without the risk of damaging neighboring components.

Included with the 74035:

1. Single-stage variable temperature insert with mount
2. 25 L LN₂ Dewar with condenser stand
3. Gas handling box
4. LN₂ transfer line with condenser assembly
5. Instrument cables
6. Sample rods and holders (NOTE: for new orders placed without a 740- or 741-VTA, these items must be ordered separately and technical support will be required to install)
   1. With 7404-S and 7407-S: 740928 sample tail and holder kit
   2. With 7410-S: 740941 sample tail and holder kit

Supplemental 74035 equipment requirements

1. Lake Shore 741-VTA variable temperature option kit
2. Sample rods and holders
   1. With 7404-S and 7407-S: 740928 sample tail and holder kit
   2. With 7410-S: 740941 sample tail and holder kit
3. Argon gas cylinder with 344 kPa (50 psi) gas regulator and 3 mm hose barb (can also be a ¼ NPT female fitting)
4. Nitrogen gas cylinder with a 344 kPa (50 psi) gas regulator and 3 mm hose barb (can also be a ¼ NPT female fitting)
5. LN₂ source to fill the provided Dewar
6. Clean compressed air (276 kPa [40 psi])
7. Mechanical vacuum pump (E2M or equivalent) kit providing sample space blank off pressure of <0.67 Pa (5 × 10^-3 Torr) for routine operation
8. Turbomolecular vacuum pump (Lake Shore TPS-FRG or equivalent) kit for cryogen transfer line maintenance—can also be used in place of the E2M rotary vacuum pump
9. A Pirani or thermocouple vacuum gauge capable of measuring pressures from 0.1 to 100 Pa (10^-3 to 1 Torr)

74018 variable temperature cryostat

This VSM cryostat is designed for rapid sample cooling with either LHe or LN₂ as well as easy sample insertion and interchange. It allows you to take measurements from 5.5 K to 450 K using LHe and from 85 K to 450 K using LN ₂. A single-point measurement can be taken at 4.2 K (LHe) and at 77.6 K (LN₂). The sample is suspended in a proprietary insulated tube constructed of nonmagnetic material.

The cryostat is mechanically isolated from the magnetometer head and sample, greatly reducing the system noise floor. It is mounted between an electromagnet base plate and a quick release mechanism located on the top of the electromagnet.

The cryostat design provides the user the capability to perform measurements economically over nearly the entire accessible temperature range with a single cryostat. The transfer line is included with the cryostat.

Included with the 74018:

1. Combination LHe/LN₂ cryostat with mount
2. LHe/LN₂ transfer line
3. Cryogen transfer kit
4. Instrument cables and related accessories
5. Sample rods and holders (NOTE: for new orders placed without a 740- or 741-VTA, these items must be ordered separately and technical support will be required to install)
   1. With 7404-S and 7407-S: 740928 sample tail and holder kit
   2. With 7410-S: 740941 sample tail and holder kit

Supplemental 74018 equipment requirements:

1. Lake Shore 741-VTA temperature option kit
2. A mechanical vacuum pump (Lake Shore E2M or similar) capable of achieving a pressure below 0.67 Pa (5 × 10^-3 Torr) and a speed of 1 m³/h, along with a KF-16 flange pump inlet
3. Access to turbomolecular vacuum pump (Lake Shore TPS-FRG or similar) capable of doing better than 1.33 × 10^-3 Pa (10^-6 Torr) for annual evacuation of transfer line vacuum space
4. LHe or LN₂ storage Dewar (Lake Shore 1220-50 or similar) with top withdraw fitting to accept the 12.7 mm (0.5 in) diameter transfer line—the transfer line furnished with the 74018 cryostat is particularly well adapted for use with 25 to 60 L storage vessels, and can be readily adapted to other capacity storage vessels (in most cases, a LHe Dewar will be provided by your local liquid gas distributor when LHe is delivered)
5. Gas cylinder with 1 to 5 psi pressure regulator to deliver clean, dry helium or nitrogen gas (depending on liquid cryogen)

74034 high temperature oven

The high temperature oven assembly enables the 7400 or 7400-S Series VSM system to be used to investigate the magnetic properties of materials at high temperature. This option consists of an electrically heated outer tube assembly with efficient thermal insulation to permit sample-zone temperature from 100 °C to 1,000 °C (373 K to 1,273 K). Temperatures from 30 °C to 1,000 °C (303 K to 1,273 K) are also possible, however, below 100 °C (373 K) measurement time increases.

The inner sample zone chamber is lined with a special heat-resistant and intrinsically non-magnetic material. A sample holder is provided that consists of a quartz tube sample rod attached to a boron-nitride sample cup. The oven secures to a special isolation mount support structure, the only special consideration being that the air gap between the coils must accommodate the 19 mm (0.75 in) outside diameter of the oven. A mechanical vacuum pump capable of maintaining inlet pressures down to 0.67 Pa (5 × 10^-3 Torr) must be supplied by the user.

This option features efficient thermal insulation, consisting of an outer vacuum chamber with reflective heat shielding. Sample zone temperatures as high as 1,000 °C are attained with a power consumption of approximately 70 W. Two results of the low power consumption are minimal magnetic interference and increased temperature uniformity in the sample zone. The oven is particularly well suited to measuring Curie temperatures of ferromagnetic or ferrimagnetic materials at temperatures up to 1,000 °C. The sensitivity of the VSM permits Curie temperature determinations at relatively low field intensities, allowing more inherently accurate determinations.

At room temperature and above, measurements may be performed on samples contained in an argon atmosphere to protect the sample from oxidation.

Included with the 74034:

1. Oven assembly with mount
2. Gas handling box
3. Nickel Curie sample cylinder
4. Instrument cables and related accessories
5. Sample rods and holders (NOTE: for new orders placed without a 740- or 741-VTA, these items must be ordered separately and technical support will be required to install)
   1. With 7404-S and 7407-S: 740928 sample tail and holder kit
   2. With 7410-S: 740941 sample tail and holder kit

Supplemental 74034 equipment requirements

1. Lake Shore 741-VTA temperature option kit
2. A mechanical vacuum pump (Lake Shore E2M or similar) capable of achieving a blanked-off pressure below 0.67 Pa (5 × 10^-3 Torr) and a pumping speed of 1 m³/h, along with a KF-16 flange pump inlet
3. Argon gas cylinder with 5 to 10 psi regulator and 3 mm (1/8 in) hose barb

741-VTA temperature option kit

The autotuning cryogenic temperature controller is used to measure and control our full suite of variable temperature options. The 741-VTA includes a Lake Shore temperature controller, thermocouple input card (when purchased for use with the high temperature oven or single stage variable temperature assembly), vacuum handling kit, mounting hardware (included with the 74035 SSVT option), flanges, hoses, connectors, and accessories. Note: only one 741-VTA is required for all variable temperature options.

74046 magnetoresistance (MR) probe

The MR probe option performs fast and accurate measurements of MR, GMR spin-valve, CMR and other magnetoresistive materials as a function of both in-plane magnetic field and temperature. This measurement option includes data acquisition, control, and analysis software to automatically extract pertinent parameters for the device under test. These include free and pinned layer parameters of both simple and synthetic spin-valve sensors.

The MR probe features four in-line pins for solder-less connection to the sample and is interchangeable with the VSM sample rod for compatibility with variable temperature and autorotation options. The temperature range of use extends from 20 K to 450 K when used with the 74018 LHe/LN₂ cryostat, 325 K to 673 K with the 74034 oven, and 100 K to 673 K with the 74035 single-stage variable temperature assembly. Angular dependent MR measurements are possible when used in combination with the 74033 autorotation option. Contact pins maintain their position on the sample while the entire assembly rotates with respect to the magnetic field. The fully automated MR software is an intuitive yet powerful user interface providing automatic control of all experimental parameters for unattended operation. Experiment recipes can be saved, retrieved, and edited, and measurement data can be displayed and exported in graphical or tabular format. Multiple step profiles can also be defined to allow for flexibility in the preparation steps and for developing annealing step process methodologies.

The MR probe option is composed of several user-replaceable parts, including contact pins, ceramic pin guides, a ceramic sample holder, a contact pressure spring, and a printed circuit board, providing the convenience of in-field maintenance.

Included with the 74046:

1. MR hardware insert
2. Lake Shore Model 776 matrix switch
3. Model 2400 Keithley sourcemeter
4. 4-wire I-V cable and MR adapter box
5. MR spare kit (2 PCBs, 1 contact pressure spring, 8 points, 1 pin guide, 1 lower holder—user-replaceable)

74033 autorotation

The rotation option allows you to automatically vary the sample orientation relative to the direction of the applied magnetic field. The angle of rotation is within a single plane defined by the direction of applied magnetic field, referred to as the x-axis. Angular variation is about the z-axis. Rotation is programmable to a resolution of <1° for rotating the sample from -10 to 730° and all parameters are measured as a function of rotation angle.

74032XY vector coils

The vector option extends the VSM measurement capabilities to facilitate investigations of anisotropic magnetic materials, allowing you to determine their vector magnetization components and susceptibility tensor. When used in combination with the 74033 autorotation option, the vector coils provide information that is essentially identical to that provided by a dedicated torque magnetometer. The 74032XY 2-inch vector coils are compatible with all variable temperature options.

E2M 2-stage rotary vacuum pump

Capable of achieving a pressure below 0.67 Pa (5 × 10^-3 Torr) at 1 m³/h, the 2-stage rotary vacuum pump is used for evacuating both the oven and cryostat vacuum spaces of our variable temperature options. This, or a similar vacuum pump, is required for daily operation of variable temperature options.

TPS-FRG turbomolecular vacuum pump station

Used to annually evacuate the cryogen transfer line of the optional cryostat and single stage variable temperature assembly (transfer line and kit are included with these options), the TPS-FRG provides vacuum to 1.33 × 10^-3 Pa (10 ^-6 Torr). In addition to annual cryogen transfer line maintenance, the turbomolecular vacuum pump can also be used in place of the E2M rotary vacuum pump for evacuating the cryostat vacuum space.

Recirculating chillers

Lake Shore offers NesLab^® recirculating chillers in order to provide a complete laboratory solution. The NesLab chillers feature a CFC-free refrigeration system.

The refrigeration system uses a hermetically sealed compressor and hot gas bypass system of temperature control. This system eliminates on/off cycling and premature wear of the compressor. Strong pumps provide continuous flow even through cooling lines with small IDs.