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Understanding NOMAD Schemas

This guide provides a detailed reference for navigating and using NOMAD schemas. Schemas are structured data templates that organize your experimental information consistently, enabling powerful search and analysis capabilities.

What are Schemas?

NOMAD schemas define the structure of your data entries. They specify:

  • Required and optional fields for your measurements
  • Data types (numbers, text, references, etc.)
  • Relationships between different entities (samples, processes, measurements)
  • Validation rules to ensure data quality

Creating a Schema Entry

Step 1: Access the Schema Creator

  1. Navigate to your upload in NOMAD Oasis

  2. Click the gray "Create from schema" button

Create from schema button

Step 2: Select Your Schema

A pop-up window appears with:

  • Text field: Enter a descriptive name for your entry
  • Dropdown menu: Select the schema type

Schema name and selection

Naming Convention

Use descriptive, systematic names that include:

  • Your username/initials
  • A sequential number
  • Material or process information
  • Specific identifiers (position, type, etc.)

Example: amazingresearcher_0042_CuZn_BL_Sputtering

Step 3: Open the Schema Interface

After selecting a schema (e.g., "Bell Jar Evaporator"), the structured data entry interface appears.

Schema interface overview

Editable Fields

  • Gray/highlighted fields can be edited
  • Click on a field to enter data
  • Different field types:
  • Text boxes for free-form input
  • Dropdowns for predefined options
  • Number fields with units
  • Date/time pickers
  • File upload areas
  • Reference fields to link other entries

Subsections

Subsections organize related information hierarchically. They are indicated by headings with expandable "+" icons.

Subsections overview

Working with Subsections

Adding a Subsection

Click the gray "+" icon next to a subsection name to create an instance.

Adding a subsection

Once added, the subsection expands to show its fields and nested subsections.

Nested Subsections

Subsections can contain other subsections, creating a hierarchy that mirrors your experimental workflow.

Nested subsections

For example: 

Process
├── Steps
│   ├── Sources
│   ├── Sample Parameters
│   └── Environment
└── Results

Single vs. Multiple Instances

Subsection Types

Single Instance Subsections

  • Allow only one instance
  • The "+" icon disappears after creation
  • Example: "Environment" - one environment per step

Multiple Instance Subsections

  • Allow multiple instances
  • The "+" icon remains after creating instances
  • Example: "Steps" - multiple steps in a process

Single vs. multiple instances

In the image above:

  • "Environment" (blue box, top) - the "+" is gone (single instance only)
  • "Steps" (blue box, bottom) - the "+" remains (can add more steps)

Viewing Multiple Instances

When you create multiple instances of a subsection, they appear in a list.

To view the list:

  1. Click on the subsection name to expand it
  2. All instances are shown with their names or numbers

List of multiple instances

Instance identification:

  • If you named the instance (e.g., "Heating", "Cooling"), that name appears
  • If unnamed, instances are numbered consecutively (1, 2, 3, etc.)

Naming Instances

Always name your instances descriptively! It makes navigation much easier when you have many steps or measurements.

Best Practices

Systematic Data Entry

  1. Work top to bottom - Fill in mandatory fields first, then add subsections
  2. Save frequently - Use the "Save" button regularly to avoid losing work
  3. Use consistent naming - Follow your lab's naming conventions
  4. Document thoroughly - Use free-text fields to add context and notes

Data Quality

  • Complete required fields - Marked with asterisks or red indicators
  • Use correct units - Pay attention to dropdown unit selectors
  • Validate references - Ensure linked entries (samples, substrates) exist
  • Review before finalizing - Check all entries are correct and complete

Efficient Navigation

  • Collapse completed sections - Click section headers to hide/show content
  • Use browser search (Ctrl+F / Cmd+F) to find specific fields quickly
  • Bookmark frequently used schemas - Keep links to common entry points

Common Schema Types

The DTU Nanolab plugin provides schemas for:

Entities (Lab Inventory)

  • Samples & Combinatorial Libraries - Track composition gradients
  • Substrates - Silicon wafers, glass, etc.
  • Targets - Sputtering targets with composition
  • Gas Supplies - Process gases
  • Instruments - Equipment tracking

Activities (Processes & Measurements)

Synthesis & Processing:

  • Sputtering Deposition
  • Thermal Evaporation
  • Rapid Thermal Processing (RTP)
  • Library Cleaving

Characterization:

  • X-ray Diffraction (XRD)
  • Energy-Dispersive X-ray (EDX)
  • X-ray Photoelectron Spectroscopy (XPS)
  • Photoluminescence (PL)
  • Ellipsometry
  • Raman Spectroscopy
  • Resistance-Temperature (RT) Measurements

Analysis:

  • Jupyter Analysis - Computational notebooks

Troubleshooting

I can't find the "+" icon

The subsection may only allow one instance, and you've already created it. Check if the subsection has expanded content below.

My entry won't save

Common causes:

  • Required fields are empty (check for red indicators)
  • Invalid data format (e.g., text in a number field)
  • Missing required subsections
  • File upload in progress

I accidentally deleted a subsection

Unfortunately, deletions are immediate. You'll need to recreate the subsection. Save frequently to minimize potential data loss!

The schema doesn't match my process

Schemas are adaptable! Use:

  • Free-text fields for additional notes
  • Custom subsections if available
  • Contact the plugin maintainers to suggest schema improvements

Need Help?

If you encounter schema-related issues:

  1. Check this guide for solutions
  2. Ask colleagues who have used similar schemas
  3. Review the Reference Documentation for field-specific details
  4. Contact the DTU Nanolab NOMAD support team