Dry Variable-Temperature Superconducting Magnet System

The dry variable-temperature superconducting magnet system (registered trademark: CryoM^®) uses only one 4K pulse-tube cryocooler or GM cryocooler to cool both the superconducting magnet and the variable-temperature insert. It offers simple operation, low running cost, and strong expandability, making it an ideal cryogenic high-magnetic-field experimental platform for scientific users. The enhanced anti-clogging design requires no external liquid-nitrogen cold trap and supports continuous operation for more than six months.

The standard CryoM integrates a 9T solenoidal superconducting magnet with a 50mm sample tube ID and a static helium environment, with a variable temperature range of 1.5K–400K. It comes standard with a four-quadrant bipolar superconducting magnet power supply, a four-channel high-precision temperature controller, and an eight-channel temperature monitor. The patented cold head suspension anti-vibration and the self-pressurizing constant-pressure gas circulation loop deliver lower vibration, faster cool-down, and better temperature stability. The standard electrical test sample rod integrates a multi-pin vacuum feedthrough, a 16-pin puck sample holder, cryogenic twisted-pair test wiring, and a low-magnetic-resistance calibrated temperature sensor (calibration range: 1K–325K). Options include 12T / 14T / 16T solenoidal superconducting magnets, a 7T split-pair superconducting magnet with optical windows, a vector superconducting magnet (9T / 2T / 2T), and high-homogeneity NMR magnets, as well as a lower base temperature down to ≤1.3K and ultra-low-vibration options.

GM cryocooler-based dry variable-temperature superconducting magnet system.（left） . 

Pulse-tube cryocooler-based dry variable-temperature superconducting magnet system.（right）

Optical variable-temperature superconducting magnet system (Model: CryoM-7S-PT) uses a valve-separated pulse-tube cryocooler as the cold source. Patented cold head suspension anti-vibration, combined with rigid internal support and flexible thermal links inside the magnet, keeps the vibration level below 100nm. It integrates a split-pair superconducting magnet providing optical channels both parallel and perpendicular to the magnetic field, with a maximum field of 7T at the sample center. The variable-temperature insert with a static helium environment provides a sample tube ID of ≥31mm and a temperature range of 1.5K–300K. Various UV, visible, infrared, and terahertz optical windows are available for optical experiments such as Raman spectroscopy, FTIR spectroscopy, and photoluminescence. The compact magnet tail makes it an ideal cryogenic high-magnetic-field optical platform. Typical applications include magneto-optical Kerr effect (MOKE) measurements, simultaneous optical-excitation and electrical-transport detection under cryogenic high magnetic fields, micro-area scanning through the optical windows for direct observation of the evolution of topological magnetic domains such as magnetic skyrmions, and using the high-transmission terahertz window to study the modulation of low-energy excitations (e.g., cyclotron resonance and plasmons) in materials by strong magnetic fields.

CryoM-7S-PT

Three-axis vector variable-temperature superconducting magnet system (Model: CryoM-9/2/2) uses a GM cryocooler or a valve-separated pulse-tube cryocooler as the cold source and integrates a 9T / 2T / 2T three-axis vector superconducting magnet with a combined field of 2T. It integrates an efficient variable-temperature insert with a static helium environment, a sample tube ID of ≥50mm, and a temperature range of 1.5K–300K.

The three-axis vector variable-temperature superconducting magnet system independently controls the magnetic-field direction and magnitude in three-dimensional space as well as the cryogenic environment. Without any physical rotation of the sample, the field can be rotated seamlessly in all directions in 3D space simply by adjusting the currents. It is widely applicable to frontier research fields such as condensed-matter physics, quantum computing, materials science, and spintronics - e.g., probing the anisotropy of novel states such as topological insulators, Dirac semimetals, and Majorana fermions by rotating the field over multiple angles; precisely controlling the alignment and flipping of electron spins in nanodevices for the development of next-generation high-speed, low-power non-volatile magnetic random-access memories; and studying the in-plane and out-of-plane quantum Hall effects and magnetic properties of graphene, transition-metal dichalcogenides, and related materials.  

Pulse-tube cryocooler-based 9/2/2 three-axis vector variable-temperature superconducting magnet system

CryoM offers a wide range of options, including single-axis / two-axis sample rods, optical sample rods, He-3 inserts / dilution-refrigerator inserts, susceptibility inserts / thermal testing inserts, lower base temperature (≤1.3K), ultra-low-vibration assemblies (e.g., cold head suspension anti-vibration, anti-vibration sandboxes), and terminal boxes. With a valve-separated pulse-tube cryocooler and cold head suspension anti-vibration, the ultra-low-vibration dry variable-temperature superconducting magnet achieves a vibration level below 100nm and is particularly suitable for low-temperature magneto-optical experiments.

CryoM-EE is an economical 1.5K 9T variable-temperature superconducting magnet with extremely high cost-effectiveness. It features a static helium, ≥30mm sample tube ID, and a nominal variable temperature range of 1.5K-300K.

CryoM-EE adopts a GM cryocooler as the cold source, with a static power consumption of only 3.5KW, which greatly saves electrical energy. The magnet cryostat features a compact design, with an OD of 43.7cm and a height of 80cm, significantly saving laboratory space.

CryoM-EE delivers excellent performance: the sweep time for 0T to 9T is within 15 minutes, and linear ramping from 1.5K to RT is within 35 minutes.

CryoM-EE has the characteristics of simple operation, low maintenance cost. Its enhanced anti-clogging design does not require an external liquid nitrogen cold trap, enabling continuous operation for more than half a year.

In addition, based on the CryoM dry variable-temperature superconducting magnet system, the cryogenic high-magnetic-field property measurement system (TKMS) integrates electromagnetic transport, Hall-effect, susceptibility, and thermal-transport measurement capabilities under cryogenic high magnetic fields, and provides multi-channel sample measurement modules that allow simultaneous testing of multiple samples.

Typical cryogenic high-magnetic-field physical property measurement system (TKMS)

The He-3 insert matches the top-loading 1.5K cryocooler (Acryo-1.5K) and the dry variable-temperature superconducting magnet (CryoM). It has a built-in cryogenic sorption pump and a sealed He-3 gas loop operating in single-shot mode. Under no-heat-load conditions, a base temperature of ≤ 270 mK is achieved and maintained for > 80h, and a cooling power of ≥ 100µW is delivered at 350mK. The standard He-3 insert operates in vacuum; an exchange-gas version and longer holding times are available as options. Typical applications include electromagnetic transport measurements, the quantum Hall effect, superconducting device testing, SQUID testing, high-pressure (DAC) experiments, and thermal-transport measurements.

Pulse-tube cryocooler-based dry variable-temperature superconducting magnet system integrated with a He-3 insert（left）；Typical He-3 insert（right）；

Cooling power versus temperature of a typical He-3 insert

Example

A He-3 insert integrating 48 low-resistance lines and four RF coaxial cables, charged with 3.5L NTP He-3 gas, reaches a base temperature below 270mK, holds the base temperature for more than 200h, and offers a temperature stability better than 1mK.

AC susceptibility module

Examples：

1、The system uses a GM cryocooler as the cold source with the patented cold head suspension and anti-vibration technique, and a top-loading design. It provides a static exchange-helium environment, a 50mm sample tube ID, a temperature range of<1.5K-300K, and a magnetic field range of ±9T, with integrated property-measurement modules allowing simultaneous testing of multiple samples.

2、The system uses a valve-separated low-vibration pulse-tube cryocooler as the cold source and the patented cold head suspension and anti-vibration technique; the nominal vibration level is below 100nm. The top-loading system provides a static exchange-helium environment, a 50 mm sample tube ID, a base temperature below 1.35K, a maximum field of 9T, and a vacuum sample rod for thermal experiments.

3、The system uses a valve-separated pulse-tube cryocooler as the cold source and the patented cold head suspension and anti-vibration technique with a top-loading design; the vibration level is 100nm. It provides a static exchange-helium environment, a 50 mm sample tube ID, a base temperature below 1.5K, an initial cool-down time below 30h, a maximum field of 12T, and a sweep time below 60min.

4、The high-field cryogenic system provides a 50.5mm sample tube ID, a temperature range of 1.5K–400K, and a magnetic field range of ±9T, with integrated property-measurement modules allowing simultaneous testing of multiple samples.

5、The system uses a valve-separated low-vibration pulse-tube cryocooler as the cold source with the patented cold head suspension and anti-vibration technique; the base temperature is below 1.5K and the maximum field is 9T. The system serves not only for electromagnetic transport measurements but also for magneto-optical measurements such as MOKE.